Android 新活动未在Eclipse中启动
我已经链接了许多活动,以构建应用程序,但最初的一个,现在我启动时,在使用时出现错误。虽然活动最初是有效的,但现在,它表明应用程序已强制关闭。有人能帮我解决这个问题吗?另外,如何连接logcat,请告诉我。我希望这能帮助你们,更好地解决问题。 谢谢 这是主活动中的代码,活动未启动的代码,下面再次给出了更改代码Android 新活动未在Eclipse中启动,android,eclipse,Android,Eclipse,我已经链接了许多活动,以构建应用程序,但最初的一个,现在我启动时,在使用时出现错误。虽然活动最初是有效的,但现在,它表明应用程序已强制关闭。有人能帮我解决这个问题吗?另外,如何连接logcat,请告诉我。我希望这能帮助你们,更好地解决问题。 谢谢 这是主活动中的代码,活动未启动的代码,下面再次给出了更改代码 package com.example.newapplication; import java.util.Random; import android.app.Activity; imp
package com.example.newapplication;
import java.util.Random;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.text.InputType;
import android.view.Gravity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.ToggleButton;
public class TextPlay extends Activity{
Button chkCommand = (Button) findViewById(R.id.b1);
ToggleButton passTog = (ToggleButton) findViewById(R.id.tB1);
EditText input = (EditText) findViewById(R.id.etCommands);
TextView display = (TextView) findViewById(R.id.tv);
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.text);
passTog.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (passTog.isChecked()){
input.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);
} else{
input.setInputType(InputType.TYPE_CLASS_TEXT);
}
}
});
chkCommand.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
String message = input.getText().toString();
if(message.contentEquals("naman")){
display.setTextColor(Color.GREEN);
display.setGravity(Gravity.CENTER);
display.setText("Password is correct");
Random crazy = new Random();
display.setTextSize(crazy.nextInt(75));
display.setTextColor(Color.rgb(crazy.nextInt(200), crazy.nextInt(256), crazy.nextInt(256)));
}
else{
display.setTextColor(Color.RED);
display.setGravity(Gravity.CENTER);
display.setText("Invalid Password");
}
}
});
}
}
logcat如下所示:
05-29 01:52:40.280: E/AndroidRuntime(892): FATAL EXCEPTION: main
05-29 01:52:40.280: E/AndroidRuntime(892): Process: com.example.newapplication, PID: 892
05-29 01:52:40.280: E/AndroidRuntime(892): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.newapplication/com.example.newapplication.TextPlay}: java.lang.NullPointerException
05-29 01:52:40.280: E/AndroidRuntime(892): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
05-29 01:52:40.280: E/AndroidRuntime(892): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
05-29 01:52:40.280: E/AndroidRuntime(892): at android.app.ActivityThread.access$800(ActivityThread.java:135)
05-29 01:52:40.280: E/AndroidRuntime(892): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
05-29 01:52:40.280: E/AndroidRuntime(892): at android.os.Handler.dispatchMessage(Handler.java:102)
05-29 01:52:40.280: E/AndroidRuntime(892): at android.os.Looper.loop(Looper.java:136)
05-29 01:52:40.280: E/AndroidRuntime(892): at android.app.ActivityThread.main(ActivityThread.java:5017)
05-29 01:52:40.280: E/AndroidRuntime(892): at java.lang.reflect.Method.invokeNative(Native Method)
05-29 01:52:40.280: E/AndroidRuntime(892): at java.lang.reflect.Method.invoke(Method.java:515)
05-29 01:52:40.280: E/AndroidRuntime(892): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-29 01:52:40.280: E/AndroidRuntime(892): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-29 01:52:40.280: E/AndroidRuntime(892): at dalvik.system.NativeStart.main(Native Method)
05-29 01:52:40.280: E/AndroidRuntime(892): Caused by: java.lang.NullPointerException
05-29 01:52:40.280: E/AndroidRuntime(892): at android.app.Activity.findViewById(Activity.java:1884)
05-29 01:52:40.280: E/AndroidRuntime(892): at com.example.newapplication.TextPlay.<init>(TextPlay.java:18)
05-29 01:52:40.280: E/AndroidRuntime(892): at java.lang.Class.newInstanceImpl(Native Method)
05-29 01:52:40.280: E/AndroidRuntime(892): at java.lang.Class.newInstance(Class.java:1208)
05-29 01:52:40.280: E/AndroidRuntime(892): at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
05-29 01:52:40.280: E/AndroidRuntime(892): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
05-29 01:52:40.280: E/AndroidRuntime(892): ... 11 more
05-29 01:52:40.280:E/AndroidRuntime(892):致命异常:main
05-29 01:52:40.280:E/AndroidRuntime(892):进程:com.example.newapplication,PID:892
05-29 01:52:40.280:E/AndroidRuntime(892):java.lang.RuntimeException:无法实例化活动组件信息{com.example.newapplication/com.example.newapplication.TextPlay}:java.lang.NullPointerException
05-29 01:52:40.280:E/AndroidRuntime(892):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2121)
05-29 01:52:40.280:E/AndroidRuntime(892):位于android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
05-29 01:52:40.280:E/AndroidRuntime(892):在android.app.ActivityThread.access$800(ActivityThread.java:135)
05-29 01:52:40.280:E/AndroidRuntime(892):在android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
05-29 01:52:40.280:E/AndroidRuntime(892):位于android.os.Handler.dispatchMessage(Handler.java:102)
05-29 01:52:40.280:E/AndroidRuntime(892):在android.os.Looper.loop(Looper.java:136)上
05-29 01:52:40.280:E/AndroidRuntime(892):位于android.app.ActivityThread.main(ActivityThread.java:5017)
05-29 01:52:40.280:E/AndroidRuntime(892):位于java.lang.reflect.Method.Invokenactive(本机方法)
05-29 01:52:40.280:E/AndroidRuntime(892):位于java.lang.reflect.Method.invoke(Method.java:515)
05-29 01:52:40.280:E/AndroidRuntime(892):位于com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-29 01:52:40.280:E/AndroidRuntime(892):位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-29 01:52:40.280:E/AndroidRuntime(892):在dalvik.system.NativeStart.main(本机方法)
05-29 01:52:40.280:E/AndroidRuntime(892):由以下原因引起:java.lang.NullPointerException
05-29 01:52:40.280:E/AndroidRuntime(892):在android.app.Activity.findViewById(Activity.java:1884)
05-29 01:52:40.280:E/AndroidRuntime(892):在com.example.newapplication.TextPlay。(TextPlay.java:18)
05-29 01:52:40.280:E/AndroidRuntime(892):位于java.lang.Class.newInstanceImpl(本机方法)
05-29 01:52:40.280:E/AndroidRuntime(892):位于java.lang.Class.newInstance(Class.java:1208)
05-29 01:52:40.280:E/AndroidRuntime(892):在android.app.Instrumentation.newActivity(Instrumentation.java:1061)上
05-29 01:52:40.280:E/AndroidRuntime(892):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
05-29 01:52:40.280:E/AndroidRuntime(892):。。。还有11个
Android清单文件如下所示:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.newapplication"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<permission android:name="android.permission.SET_WALLPAPER"></permission>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.newapplication.Splash"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name="com.example.newapplication.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.example.newapplication.MAINACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.example.newapplication.TextPlay"
android:label="@string/app_name"
android:screenOrientation="portrait"
>
<intent-filter>
<action android:name="com.example.newapplication.TEXTPLAY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.example.newapplication.Email"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.example.newapplication.EMAIL" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name="com.example.newapplication.Camera"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.example.newapplication.CAMERA" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
将此代码移动到
TextPlay.java
Button chkCommand = (Button) findViewById(R.id.b1);
ToggleButton passTog = (ToggleButton) findViewById(R.id.tB1);
EditText input = (EditText) findViewById(R.id.etCommands);
TextView display = (TextView) findViewById(R.id.tv);
之后
setContentView(R.layout.text);
当您在设置xml文件内容之前试图查找视图时,会出现空指针异常。希望这有帮助。此代码:
Button chkCommand = (Button) findViewById(R.id.b1);
ToggleButton passTog = (ToggleButton) findViewById(R.id.tB1);
EditText input = (EditText) findViewById(R.id.etCommands);
TextView display = (TextView) findViewById(R.id.tv);
它应该位于OnCreate方法内部和下面的setContentView(R.layout.text)代码>这一行在类中可以声明变量初始化是在OnCreate方法中完成的
public class TextPlay extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.text);
Button chkCommand = (Button) findViewById(R.id.b1);
ToggleButton passTog = (ToggleButton) findViewById(R.id.tB1);
EditText input = (EditText) findViewById(R.id.etCommands);
TextView display = (TextView) findViewById(R.id.tv);
passTog.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (passTog.isChecked()){
input.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);
} else{
input.setInputType(InputType.TYPE_CLASS_TEXT);
}
}
});
chkCommand.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
String message = input.getText().toString();
if(message.contentEquals("naman")){
display.setTextColor(Color.GREEN);
display.setGravity(Gravity.CENTER);
display.setText("Password is correct");
Random crazy = new Random();
display.setTextSize(crazy.nextInt(75));
display.setTextColor(Color.rgb(crazy.nextInt(200), crazy.nextInt(256), crazy.nextInt(256)));
}
else{
display.setTextColor(Color.RED);
display.setGravity(Gravity.CENTER);
display.setText("Invalid Password");
}
}
});
}
}
添加代码会更有帮助。只需转到屏幕底部的Logcat选项卡,并以红色复制所有内容。您必须按shift
键从Logcat中选择行,然后按ctrl+c
编辑您的问题。对于Logcat,发布AndroidManifest.xml
,无需提供任何链接,只需复制logcat数据并粘贴它,这样我们就可以帮助…好的。成功了。谢谢我本应该向程序中添加一个新方法,使程序看起来有点干净,但我没有这样做,而且,据推测它会给出空点异常的错误。@user3676294很高兴我能提供帮助:)始终欢迎。您想在JAVA中使用final和this吗?我对编程非常陌生,上面的代码在使用时显示了将所有变量的数据类型声明为final的错误。这样做后,程序运行正常。那么,这篇期末报告有什么用呢?如果你能简单介绍一下,或者在网上推荐一些学习资料链接。当然@用户3676294参考和
public class TextPlay extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.text);
Button chkCommand = (Button) findViewById(R.id.b1);
ToggleButton passTog = (ToggleButton) findViewById(R.id.tB1);
EditText input = (EditText) findViewById(R.id.etCommands);
TextView display = (TextView) findViewById(R.id.tv);
passTog.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (passTog.isChecked()){
input.setInputType(InputType.TYPE_CLASS_TEXT | InputType.TYPE_TEXT_VARIATION_PASSWORD);
} else{
input.setInputType(InputType.TYPE_CLASS_TEXT);
}
}
});
chkCommand.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
String message = input.getText().toString();
if(message.contentEquals("naman")){
display.setTextColor(Color.GREEN);
display.setGravity(Gravity.CENTER);
display.setText("Password is correct");
Random crazy = new Random();
display.setTextSize(crazy.nextInt(75));
display.setTextColor(Color.rgb(crazy.nextInt(200), crazy.nextInt(256), crazy.nextInt(256)));
}
else{
display.setTextColor(Color.RED);
display.setGravity(Gravity.CENTER);
display.setText("Invalid Password");
}
}
});
}
}