Java ImageButton打开新活动

我正在构建一个android应用程序，在主布局上我有3个图像按钮，当单击这些按钮时，它们都必须打开一个新的活动

当我运行应用程序并按下它们时，应用程序会崩溃。这是我正在使用的代码：

MainActivity.java

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ImageButton converterbtn = (ImageButton)findViewById(R.id.btnConvert);
    ImageButton placesbtn = (ImageButton)findViewById(R.id.imagBtnPlace);
    ImageButton weatherbtn = (ImageButton)findViewById(R.id.imgbtnweather);

     //Open Weather Activity
    if (weatherbtn.isPressed() == true) {
        weatherbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent intent = new Intent(getApplicationContext(), weather_mainActivity.class);
                startActivity(intent);
            }

        }); //Open Currency Activity
    }else if (converterbtn.isPressed() == true) {
        converterbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent intent1 = new Intent(getApplicationContext(), CurrencyConverter_MainActivity.class);
                startActivity(intent1);
            }
        });//Open Places Activity
    } else if (placesbtn.isPressed()) {
        placesbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent intent1 = new Intent(getApplicationContext(), Places_mainActivity.class);
                startActivity(intent1);
            }
        });
    }
}

package com.android.example.cwapp;


import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.drawable.Drawable;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import com.squareup.okhttp.Call;
import com.squareup.okhttp.Callback;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;

import butterknife.ButterKnife;
import butterknife.InjectView;


public class weather_mainActivity extends AppCompatActivity {


public static final String TAG = weather_mainActivity.class.getSimpleName();

private CurrentWeather mCurrentWeather;

LocationManager locationManager;

@InjectView(R.id.timeLabel) TextView mTimeLabel;
@InjectView(R.id.temperatureLabel)TextView mTemperatureLabel;
@InjectView(R.id.humidityValue)TextView mHumidityValue;
@InjectView(R.id.precipValue)TextView mPrecipValue;
@InjectView(R.id.summaryLabel)TextView mSummaryLabel;
@InjectView(R.id.iconImageView)ImageView mIconImageView;
@InjectView(R.id.refreshImageView)ImageView mRefreshImageView;
@InjectView(R.id.progressBar)ProgressBar mProgressBar;
@InjectView(R.id.locationLabel)TextView mLocation;

public double latitude /*= 34.7720*/;
public double longitude /*= 32.4297*/;

//Location Manager
private boolean checkLocation() {
    if (!isLocationEnabled())
        showAlert();
    return isLocationEnabled();
}

private void showAlert() {
    final AlertDialog.Builder dialog = new AlertDialog.Builder(this);
    dialog.setTitle("Enable Location")
            .setMessage("Your Locations Settings is set to 'Off'.\nPlease Enable Location to " +
                    "use this app")
            .setPositiveButton("Location Settings", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                    Intent myIntent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                    startActivity(myIntent);
                }
            })
            .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                }
            });
    dialog.show();
}
private boolean isLocationEnabled() {
    return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) ||
            locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
}

private final LocationListener locationListenerBest = new LocationListener() {
    public void onLocationChanged(Location location) {
        longitude = location.getLongitude();
        latitude = location.getLatitude();
    }

    @Override
    public void onStatusChanged(String s, int i, Bundle bundle) {

    }

    @Override
    public void onProviderEnabled(String s) {

    }

    @Override
    public void onProviderDisabled(String s) {

    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ButterKnife.inject(this);

    mProgressBar.setVisibility(View.INVISIBLE);



    mRefreshImageView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getForecast(latitude, longitude);
        }
    });

    getForecast(latitude, longitude);

    Log.d(TAG, "Main UI code is running!");
}

private void getForecast(double latitude, double longitude) {
    String apiKey = "6180f6e1b6747c1da3cb4638ea9d2961";
    String forecastUrl = "https://api.forecast.io/forecast/" + apiKey +
            "/" + latitude + "," + longitude;

    if (isNetworkAvailable()) {
        toggleRefresh();

        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(forecastUrl)
                .build();

        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Request request, IOException e) {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        toggleRefresh();
                    }
                });
                alertUserAboutError();
            }

            @Override
            public void onResponse(Response response) throws IOException {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        toggleRefresh();
                    }
                });

                try {
                    String jsonData = response.body().string();
                    Log.v(TAG, jsonData);
                    if (response.isSuccessful()) {
                        mCurrentWeather = getCurrentDetails(jsonData);
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                updateDisplay();
                            }
                        });
                    } else {
                        alertUserAboutError();
                    }
                } catch (IOException e) {
                    Log.e(TAG, "Exception caught: ", e);
                } catch (JSONException e) {
                    Log.e(TAG, "Exception caught: ", e);
                }
            }
        });
    } else {
        Toast.makeText(this, getString(R.string.network_unavailable_message),
                Toast.LENGTH_LONG).show();
    }
}

private void toggleRefresh() {
    if (mProgressBar.getVisibility() == View.INVISIBLE) {
        mProgressBar.setVisibility(View.VISIBLE);
        mRefreshImageView.setVisibility(View.INVISIBLE);
    } else {
        mProgressBar.setVisibility(View.INVISIBLE);
        mRefreshImageView.setVisibility(View.VISIBLE);
    }
}

private void updateDisplay() {
    float temp = mCurrentWeather.getTemperature();
    String temp2 = Float.toString((temp - 32) * (5 / 9));
    mTemperatureLabel.setText(temp2 + "");
    mTimeLabel.setText("At " + mCurrentWeather.getFormattedTime() + " it will be");
    mHumidityValue.setText(mCurrentWeather.getHumidity() + "");
    mPrecipValue.setText(mCurrentWeather.getPrecipChance() + "%");
    mSummaryLabel.setText(mCurrentWeather.getSummary());
    mLocation.setText(mCurrentWeather.getTimeZone());


    Drawable drawable = getResources().getDrawable(mCurrentWeather.getIconId());
    mIconImageView.setImageDrawable(drawable);
}

private CurrentWeather getCurrentDetails(String jsonData) throws JSONException {
    JSONObject forecast = new JSONObject(jsonData);
    String timezone = forecast.getString("timezone");
    Log.i(TAG, "From JSON: " + timezone);

    JSONObject currently = forecast.getJSONObject("currently");

    CurrentWeather currentWeather = new CurrentWeather();
    currentWeather.setHumidity(currently.getDouble("humidity"));
    currentWeather.setTime(currently.getLong("time"));
    currentWeather.setIcon(currently.getString("icon"));
    currentWeather.setPrecipChance(currently.getDouble("precipProbability"));
    currentWeather.setSummary(currently.getString("summary"));
    currentWeather.setTemperature(currently.getDouble("temperature"));
    currentWeather.setTimeZone(timezone);

    Log.d(TAG, currentWeather.getFormattedTime());

    return currentWeather;
}


private boolean isNetworkAvailable() {
    ConnectivityManager manager = (ConnectivityManager)
            getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = manager.getActiveNetworkInfo();
    boolean isAvailable = false;
    if (networkInfo != null && networkInfo.isConnected()) {
        isAvailable = true;
    }

    return isAvailable;
}

private void alertUserAboutError() {
    AlertDialogFragment_weather dialog = new AlertDialogFragment_weather();
    dialog.show(getFragmentManager(), "error_dialog");
}

Manifest.xml

 <activity android:name=".CurrencyConverter_MainActivity"/>
 <activity android:name=".weather_mainActivity"/>

Weather\u main activity.java

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ImageButton converterbtn = (ImageButton)findViewById(R.id.btnConvert);
    ImageButton placesbtn = (ImageButton)findViewById(R.id.imagBtnPlace);
    ImageButton weatherbtn = (ImageButton)findViewById(R.id.imgbtnweather);

     //Open Weather Activity
    if (weatherbtn.isPressed() == true) {
        weatherbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent intent = new Intent(getApplicationContext(), weather_mainActivity.class);
                startActivity(intent);
            }

        }); //Open Currency Activity
    }else if (converterbtn.isPressed() == true) {
        converterbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent intent1 = new Intent(getApplicationContext(), CurrencyConverter_MainActivity.class);
                startActivity(intent1);
            }
        });//Open Places Activity
    } else if (placesbtn.isPressed()) {
        placesbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent intent1 = new Intent(getApplicationContext(), Places_mainActivity.class);
                startActivity(intent1);
            }
        });
    }
}

package com.android.example.cwapp;


import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.graphics.drawable.Drawable;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import com.squareup.okhttp.Call;
import com.squareup.okhttp.Callback;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;

import butterknife.ButterKnife;
import butterknife.InjectView;


public class weather_mainActivity extends AppCompatActivity {


public static final String TAG = weather_mainActivity.class.getSimpleName();

private CurrentWeather mCurrentWeather;

LocationManager locationManager;

@InjectView(R.id.timeLabel) TextView mTimeLabel;
@InjectView(R.id.temperatureLabel)TextView mTemperatureLabel;
@InjectView(R.id.humidityValue)TextView mHumidityValue;
@InjectView(R.id.precipValue)TextView mPrecipValue;
@InjectView(R.id.summaryLabel)TextView mSummaryLabel;
@InjectView(R.id.iconImageView)ImageView mIconImageView;
@InjectView(R.id.refreshImageView)ImageView mRefreshImageView;
@InjectView(R.id.progressBar)ProgressBar mProgressBar;
@InjectView(R.id.locationLabel)TextView mLocation;

public double latitude /*= 34.7720*/;
public double longitude /*= 32.4297*/;

//Location Manager
private boolean checkLocation() {
    if (!isLocationEnabled())
        showAlert();
    return isLocationEnabled();
}

private void showAlert() {
    final AlertDialog.Builder dialog = new AlertDialog.Builder(this);
    dialog.setTitle("Enable Location")
            .setMessage("Your Locations Settings is set to 'Off'.\nPlease Enable Location to " +
                    "use this app")
            .setPositiveButton("Location Settings", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                    Intent myIntent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                    startActivity(myIntent);
                }
            })
            .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface paramDialogInterface, int paramInt) {
                }
            });
    dialog.show();
}
private boolean isLocationEnabled() {
    return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) ||
            locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
}

private final LocationListener locationListenerBest = new LocationListener() {
    public void onLocationChanged(Location location) {
        longitude = location.getLongitude();
        latitude = location.getLatitude();
    }

    @Override
    public void onStatusChanged(String s, int i, Bundle bundle) {

    }

    @Override
    public void onProviderEnabled(String s) {

    }

    @Override
    public void onProviderDisabled(String s) {

    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ButterKnife.inject(this);

    mProgressBar.setVisibility(View.INVISIBLE);



    mRefreshImageView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getForecast(latitude, longitude);
        }
    });

    getForecast(latitude, longitude);

    Log.d(TAG, "Main UI code is running!");
}

private void getForecast(double latitude, double longitude) {
    String apiKey = "6180f6e1b6747c1da3cb4638ea9d2961";
    String forecastUrl = "https://api.forecast.io/forecast/" + apiKey +
            "/" + latitude + "," + longitude;

    if (isNetworkAvailable()) {
        toggleRefresh();

        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(forecastUrl)
                .build();

        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Request request, IOException e) {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        toggleRefresh();
                    }
                });
                alertUserAboutError();
            }

            @Override
            public void onResponse(Response response) throws IOException {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        toggleRefresh();
                    }
                });

                try {
                    String jsonData = response.body().string();
                    Log.v(TAG, jsonData);
                    if (response.isSuccessful()) {
                        mCurrentWeather = getCurrentDetails(jsonData);
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                updateDisplay();
                            }
                        });
                    } else {
                        alertUserAboutError();
                    }
                } catch (IOException e) {
                    Log.e(TAG, "Exception caught: ", e);
                } catch (JSONException e) {
                    Log.e(TAG, "Exception caught: ", e);
                }
            }
        });
    } else {
        Toast.makeText(this, getString(R.string.network_unavailable_message),
                Toast.LENGTH_LONG).show();
    }
}

private void toggleRefresh() {
    if (mProgressBar.getVisibility() == View.INVISIBLE) {
        mProgressBar.setVisibility(View.VISIBLE);
        mRefreshImageView.setVisibility(View.INVISIBLE);
    } else {
        mProgressBar.setVisibility(View.INVISIBLE);
        mRefreshImageView.setVisibility(View.VISIBLE);
    }
}

private void updateDisplay() {
    float temp = mCurrentWeather.getTemperature();
    String temp2 = Float.toString((temp - 32) * (5 / 9));
    mTemperatureLabel.setText(temp2 + "");
    mTimeLabel.setText("At " + mCurrentWeather.getFormattedTime() + " it will be");
    mHumidityValue.setText(mCurrentWeather.getHumidity() + "");
    mPrecipValue.setText(mCurrentWeather.getPrecipChance() + "%");
    mSummaryLabel.setText(mCurrentWeather.getSummary());
    mLocation.setText(mCurrentWeather.getTimeZone());


    Drawable drawable = getResources().getDrawable(mCurrentWeather.getIconId());
    mIconImageView.setImageDrawable(drawable);
}

private CurrentWeather getCurrentDetails(String jsonData) throws JSONException {
    JSONObject forecast = new JSONObject(jsonData);
    String timezone = forecast.getString("timezone");
    Log.i(TAG, "From JSON: " + timezone);

    JSONObject currently = forecast.getJSONObject("currently");

    CurrentWeather currentWeather = new CurrentWeather();
    currentWeather.setHumidity(currently.getDouble("humidity"));
    currentWeather.setTime(currently.getLong("time"));
    currentWeather.setIcon(currently.getString("icon"));
    currentWeather.setPrecipChance(currently.getDouble("precipProbability"));
    currentWeather.setSummary(currently.getString("summary"));
    currentWeather.setTemperature(currently.getDouble("temperature"));
    currentWeather.setTimeZone(timezone);

    Log.d(TAG, currentWeather.getFormattedTime());

    return currentWeather;
}


private boolean isNetworkAvailable() {
    ConnectivityManager manager = (ConnectivityManager)
            getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = manager.getActiveNetworkInfo();
    boolean isAvailable = false;
    if (networkInfo != null && networkInfo.isConnected()) {
        isAvailable = true;
    }

    return isAvailable;
}

private void alertUserAboutError() {
    AlertDialogFragment_weather dialog = new AlertDialogFragment_weather();
    dialog.show(getFragmentManager(), "error_dialog");
}

})

运行日志

  01-09 21:29:30.827 5610-5610/? E/memtrack: Couldn't load memtrack module (No such file or directory)
01-09 21:29:30.827 5610-5610/? E/android.os.Debug: failed to load memtrack module: -2
01-09 21:29:30.864 5610-5627/? E/art: Thread attaching while runtime is shutting down: Binder_2
01-09 21:29:30.869 5614-5614/? E/memtrack: Couldn't load memtrack module (No such file or directory)
01-09 21:29:30.870 5614-5614/? E/android.os.Debug: failed to load memtrack module: -2
01-09 21:29:30.916 1548-1596/? E/InputDispatcher: channel '6ba3a14 com.android.example.cwapp/com.android.example.cwapp.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
01-09 21:29:31.830 5633-5633/? E/memtrack: Couldn't load memtrack module (No such file or directory)
01-09 21:29:31.830 5633-5633/? E/android.os.Debug: failed to load memtrack module: -2
01-09 21:29:32.033 1195-1309/? E/SurfaceFlinger: ro.sf.lcd_density must be defined as a build property
01-09 21:29:33.170 1921-2145/? E/Surface: getSlotFromBufferLocked: unknown buffer: 0xedc344f0
01-09 21:30:01.551 5641-5654/? E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f44b819a240
01-09 21:30:02.902 5641-5654/? E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f44b1cf8310
01-09 21:30:04.739 5641-5654/? E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f44b819b580
01-09 21:30:06.655 5641-5654/? E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f44b1cf8380
01-09 21:30:08.253 5641-5654/? E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f44b1bed700
01-09 21:30:09.115 5641-5641/? E/AndroidRuntime: FATAL EXCEPTION: main
                                                 Process: com.android.example.cwapp, PID: 5641
                                                 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.example.cwapp/com.android.example.cwapp.Places_mainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
                                                     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
                                                     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                                                     at android.app.ActivityThread.-wrap11(ActivityThread.java)
                                                     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
                                                     at android.os.Handler.dispatchMessage(Handler.java:102)
                                                     at android.os.Looper.loop(Looper.java:148)
                                                     at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                     at java.lang.reflect.Method.invoke(Native Method)
                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
                                                  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference
                                                     at com.android.example.cwapp.Places_mainActivity.onCreate(Places_mainActivity.java:36)
                                                     at android.app.Activity.performCreate(Activity.java:6237)
                                                     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
                                                     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
                                                     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
                                                     at android.app.ActivityThread.-wrap11(ActivityThread.java) 
                                                     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
                                                     at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                     at android.os.Looper.loop(Looper.java:148) 
                                                     at android.app.ActivityThread.main(ActivityThread.java:5417) 
                                                     at java.lang.reflect.Method.invoke(Native Method) 
                                                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                                                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
01-09 21:30:11.307 1548-1601/? E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f44b1c8f020
01-09 21:30:11.326 1548-1937/? E/JavaBinder: !!! FAILED BINDER TRANSACTION !!!  (parcel size = 104)

---

在mainfest中添加

CurrentWeather.class

活动，如下所示

<activity android:name=".CurrencyConverter_MainActivity"/>
<activity android:name=".weather_mainActivity"/>
<activity android:name=".CurrentWeather"/>

---

您应该显示堆栈跟踪，但不需要View.OnClickListner，也不确定这是否是原因，只需使用weatherbtn.setOnClickListener（新的OnClickListener（）{

---

除此之外，您对活动的调用方式没有任何错误。

man抱歉，发布了错误的代码。“weather\u main activity.class”假设存在而不是.CurrentWeather.class。请提供weather_mainActivity.class的.xml文件。可能有问题。你现在可以看一下吗？哦，奇怪……好吧，它不应该存在，那么你可以共享stacktrace吗？因为这是第二个问题，你可以撤销我说的内容，并在第一次访问时共享原始的stacktrace问题。现在发布！！这不是stacktrace，请转到“跑步”选项卡（最左下角）看看当你点击该按钮时打印的内容有没有一种使用stackoverflow聊天的方法？现在发布，希望它是正确的…你的意思是什么？因为它比在这里来回发送消息更简单。转到run窗口，ctrl+f“exception”共享整行和后面的几行，特别是如果你看到couple有不同颜色的单词。问题在places_mainactivity类中。请发布代码。01-09 21:30:09.115 5641-5641/？e/AndroidRuntime:致命异常：主进程：com.android.example.cwapp，PID:5641 java.lang.RuntimeException:Unable启动活动组件信息{com.android.example.cwapp/com.android.example.cwapp.Places_mainActivity}:java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法'void android.widget.ListView.setAdapter（android.widget.ListAdapter）'