Java 为什么我的android应用程序在启动新活动时崩溃？

当我尝试启动新活动uploadLocation.class时，我的应用程序不断崩溃。 没有突出显示错误，我无法在uploadLocation类中进行调试

我已将权限添加到清单中

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

除了下面的MainActivity.java之外，该类还可以工作，因为它应该完成下面的MainActivity.java

import android.content.Context;
import android.content.Intent;
import android.location.Location;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;

public class MainActivity extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks,
    GoogleApiClient.OnConnectionFailedListener, LocationListener {

Button uploadButton;
TextView latitudeView, longitudeView, networkView;
Location lastKnownLocation;
private GoogleApiClient googleApiClient;
private LocationRequest locationRequest;
String latString1, lonString1;

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

    uploadButton = (Button) findViewById(R.id.uploadButton);
    networkView = (TextView) findViewById(R.id.networkView);

    latitudeView = (TextView)findViewById(R.id.latitudeView);
    longitudeView = (TextView)findViewById(R.id.longitudeView);

    buildGoogleApiClient();

    ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
    if (networkInfo != null && networkInfo.isConnected()){
        networkView.setVisibility(View.INVISIBLE);
    } else {
        uploadButton.setEnabled(false);
    }


}

public void uploadMyLocation (View view){
    startActivity(new Intent(this, uploadLocation.class));
}

@Override
public void onConnected(Bundle bundle) {
    locationRequest = LocationRequest.create();
    locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    locationRequest.setInterval(100); // location updated every second

    LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, locationRequest, this);
    lastKnownLocation = LocationServices.FusedLocationApi.getLastLocation(googleApiClient);

    if(lastKnownLocation != null){
        latString1 = String.valueOf(lastKnownLocation.getLatitude());
        lonString1 = String.valueOf(lastKnownLocation.getLongitude());
    }
    updateUI();
}

@Override
public void onLocationChanged(Location location) {
    latString1 = String.valueOf(location.getLatitude());
    lonString1 = String.valueOf(location.getLongitude());
    updateUI();
}



@Override
public void onConnectionSuspended(int i) {

}

@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
    buildGoogleApiClient();
}

synchronized void buildGoogleApiClient(){
    googleApiClient = new GoogleApiClient.Builder(this).addConnectionCallbacks(this).addOnConnectionFailedListener(this).addApi(LocationServices.API).build();
}

@Override
protected void onStart(){
    super.onStart();
    googleApiClient.connect();
}

@Override
protected void onDestroy(){
    super.onDestroy();
    googleApiClient.disconnect();
}

void updateUI(){
    latitudeView.setText(latString1);
    longitudeView.setText(lonString1);
}
}

上传位置

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
import java.net.URLEncoder;

public class uploadLocation extends AppCompatActivity {

TextView myLatitudeView, myLongitudeView, latitudeView, longitudeView;
String latString, lonString;

public void uploadInfo(View view){
    latString = latitudeView.getText().toString();
    lonString = longitudeView.getText().toString();
    myLatitudeView = (TextView)findViewById(R.id.myLatitudeView);
    myLongitudeView = (TextView)findViewById(R.id.myLongitudeView);
    myLatitudeView.setText(latString);
    myLongitudeView.setText(lonString);
    BackgroundOp backgroundOp = new BackgroundOp();
    backgroundOp.execute(latString, lonString);
    finish();
}

class BackgroundOp extends AsyncTask<String, Void, String>{

    String myUrl;

    @Override
    protected void onPreExecute() {
        myUrl = "http://[web address]/[php script]";
    }

    @Override
    protected String doInBackground(String... data) {
        String latString, lonString;
        latString = data [0];
        lonString = data [1];

        try {
            URL url = new URL(myUrl);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String myDataStream = URLEncoder.encode("Latitude", "UTF-8") + "=" + URLEncoder.encode(latString, "UTF-8") + "&" +
                    URLEncoder.encode("Longitude", "UTF-8") + "=" + URLEncoder.encode(lonString, "UTF-8");
            bufferedWriter.write(myDataStream);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            inputStream.close();
            httpURLConnection.disconnect();
            return "Upload Successful";

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (ProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onProgressUpdate(Void... values) {
        super.onProgressUpdate(values);
    }

    @Override
    protected void onPostExecute(String result) {
        Toast.makeText(getApplicationContext(), result, Toast.LENGTH_LONG).show();
    }
}
}

---

请告知您，每项活动都需要按照doc覆盖方法

此方法在活动启动时调用。这就是大多数初始化应该做的：调用setContentViewint来扩展活动的UI，使用FindViewByDint以编程方式与UI中的小部件交互

我建议您重写必要的方法，并且不要忘记在onCreate方法中调用super.onCreate

更新：

我发现了你的错误，那是因为这个属性

android:onClick="uploadInfo"

因为您提供的XML是activity_main.XML。您正在另一个活动中使用uploadInfo方法。因此，我建议您要么删除此属性，要么在MainActivity中创建uploadInfo方法，而不是在uploadLocation活动中创建uploadInfo方法

---

要获得提示，您可以按该属性上的Alt+Enter，并按照Android Studio的建议创建方法uploadInfo。

我认为您尚未将新活动添加到Android清单文件中。 尝试添加这个

<activity android:name=".uploadLocation">
</activity>

---

当我在Android上开始开发时，我遇到了同样的问题，我用这个来修复我的应用程序崩溃：

尝试扩展活动，而不是扩展活动

---

如果不起作用，可能您的组件为空，请检查是否实例化XML中声明的所有组件。

您必须获得崩溃报告，请共享此报告。您可能在某个地方有空组件。我知道这听起来很简单。但很多时候，当你打开一个新的活动时，它依赖于传入的内容。如果那东西不在那里，它就会崩溃。在代码编辑器中你不会看到任何关于它的信息。检查您的日志。好的，最后我发现了您的错误，请查看我的更新答案。谢谢，我在编译器日志中看到了这一点，并添加了它，重新运行它仍然会崩溃。这里的问题与Activity vs AppCompatiActivity无关。只有当OP没有使用基于AppCompat的主题时，这才是一个问题。这里真正的问题是uploadInfo中没有onCreate，并且它有一个非默认构造函数。此外，按照onClick属性的指定方式，它将找不到要执行的方法。

   03-24 16:11:26.893 17436-17436/? I/art: Late-enabling -Xcheck:jni
03-24 16:11:27.044 17436-17467/com.cityuni.sophie.locationapp I/GMPM: App measurement is starting up
03-24 16:11:27.058 17436-17467/com.cityuni.sophie.locationapp E/GMPM: getGoogleAppId failed with status: 10
03-24 16:11:27.059 17436-17467/com.cityuni.sophie.locationapp E/GMPM: Uploading is not possible. App measurement disabled
03-24 16:11:27.155 17436-17475/com.cityuni.sophie.locationapp D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
03-24 16:11:27.160 17436-17436/com.cityuni.sophie.locationapp D/Atlas: Validating map...
03-24 16:11:27.208 17436-17475/com.cityuni.sophie.locationapp I/Adreno: QUALCOMM build                   : 40d, I21dda
                                                                        Build Date                       : 08/24/15
                                                                        OpenGL ES Shader Compiler Version: E031.25
                                                                        Local Branch                     : 
                                                                        Remote Branch                    : quic/LA.4.1.1_r9
                                                                        Remote Branch                    : NONE
                                                                        Reconstruct Branch               : NOTHING
03-24 16:11:27.216 17436-17475/com.cityuni.sophie.locationapp I/OpenGLRenderer: Initialized EGL, version 1.4
03-24 16:11:27.225 17436-17475/com.cityuni.sophie.locationapp D/OpenGLRenderer: Enabling debug mode 0
03-24 16:11:27.388 17436-17436/com.cityuni.sophie.locationapp I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@3563b026 time:407225888
03-24 16:11:45.883 17436-17436/com.cityuni.sophie.locationapp D/AndroidRuntime: Shutting down VM
03-24 16:11:45.902 17436-17436/com.cityuni.sophie.locationapp E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                Process: com.cityuni.sophie.locationapp, PID: 17436
                                                                                java.lang.IllegalStateException: Could not find method uploadInfo(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatButton with id 'uploadButton'
                                                                                    at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:325)
                                                                                    at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
                                                                                    at android.view.View.performClick(View.java:4861)
                                                                                    at android.view.View$PerformClick.run(View.java:19980)
                                                                                    at android.os.Handler.handleCallback(Handler.java:739)
                                                                                    at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                    at android.os.Looper.loop(Looper.java:211)
                                                                                    at android.app.ActivityThread.main(ActivityThread.java:5373)
                                                                                    at java.lang.reflect.Method.invoke(Native Method)
                                                                                    at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)
                                                                                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)
03-24 16:12:19.041 17436-17436/com.cityuni.sophie.locationapp I/Process: Sending signal. PID: 17436 SIG: 9

android:onClick="uploadInfo"

<activity android:name=".uploadLocation">
</activity>