我是 android 的新手，我尝试运行我的 android 应用程序，它在控制台上没有给出任何错误，但我在模拟器中打开应用程序，我收到 toast 应用程序未安装在您的手机上 same query .在这个论坛上提问，他们说如果您在 AndroidManifest.xml 中声明了两次 MainActivity，就会发生这种情况，我尝试这样做，但不会成功

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.intent"
android:versionCode="1"
android:versionName="1.0" > 
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />

<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
    android:name=".Activity1"
    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=".Activity2"
android:label="@string/app_name">
   </activity>
 </application>
</manifest>

Activity 1

package com.example.intent;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class Activity1 extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_activity1);
     addListenerOnButton();
}

 public void addListenerOnButton() {
     final Context context = this;
    Button b1=(Button)findViewById(R.id.textView1);
    b1.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
             Intent intent = new Intent(context,Activity2.class);
             startActivity(intent); 

        }
    });

}



}

Activity2.java

package com.example.intent;

import android.app.Activity;
import android.os.Bundle;

 public class Activity2  extends Activity{
 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity2);

    }
 }

activity_activity1.xml-->Activity1.java

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/linearLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >    
 <TextView
     android:id="@+id/textView1"
     android:layout_width="252dp"
     android:layout_height="40dp"
     android:layout_gravity="center_horizontal"
     android:text="@string/t1"
     android:textAppearance="?android:attr/textAppearanceLarge" />
    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/intent"/>
    </LinearLayout>

activity_activity2.xml --> Activity2.java

<?xml version="1.0" encoding="utf-8"?>
   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/t2"
     />
    </LinearLayout>

字符串.xml

 <resources>
  <string name="app_name">Intent</string>
  <string name="intent">Click me to Another Screen</string>
  <string name="t1">I am Screen 1!</string>
  <string name="t2">I am Screen 2!</string>
  <string name="hello_world">Hello world!</string>
  <string name="menu_settings">Settings</string>
  <string name="title_activity_activity1">Activity1</string>
 </resources>

日志猫

      09-07 17:10:01.281: D/AndroidRuntime(756): Shutting down VM
09-07 17:10:01.291: W/dalvikvm(756): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
09-07 17:10:01.301: E/AndroidRuntime(756): FATAL EXCEPTION: main
09-07 17:10:01.301: E/AndroidRuntime(756): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.intent/com.example.intent.Activity1}: java.lang.ClassCastException: android.widget.TextView
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.os.Looper.loop(Looper.java:123)
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.app.ActivityThread.main(ActivityThread.java:4627)
09-07 17:10:01.301: E/AndroidRuntime(756):  at java.lang.reflect.Method.invokeNative(Native Method)
09-07 17:10:01.301: E/AndroidRuntime(756):  at java.lang.reflect.Method.invoke(Method.java:521)
09-07 17:10:01.301: E/AndroidRuntime(756):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-07 17:10:01.301: E/AndroidRuntime(756):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-07 17:10:01.301: E/AndroidRuntime(756):  at dalvik.system.NativeStart.main(Native Method)
09-07 17:10:01.301: E/AndroidRuntime(756): Caused by: java.lang.ClassCastException: android.widget.TextView
09-07 17:10:01.301: E/AndroidRuntime(756):  at com.example.intent.Activity1.addListenerOnButton(Activity1.java:22)
09-07 17:10:01.301: E/AndroidRuntime(756):  at com.example.intent.Activity1.onCreate(Activity1.java:17)
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-07 17:10:01.301: E/AndroidRuntime(756):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
09-07 17:10:01.301: E/AndroidRuntime(756):  ... 11 more
09-07 17:10:10.700: I/Process(756): Sending signal. PID: 756 SIG: 9
09-07 17:15:13.781: D/AndroidRuntime(812): Shutting down VM
09-07 17:15:13.781: W/dalvikvm(812): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
09-07 17:15:13.801: E/AndroidRuntime(812): FATAL EXCEPTION: main
09-07 17:15:13.801: E/AndroidRuntime(812): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.intent/com.example.intent.Activity1}: java.lang.ClassCastException: android.widget.TextView
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.os.Looper.loop(Looper.java:123)
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.app.ActivityThread.main(ActivityThread.java:4627)
09-07 17:15:13.801: E/AndroidRuntime(812):  at java.lang.reflect.Method.invokeNative(Native Method)
09-07 17:15:13.801: E/AndroidRuntime(812):  at java.lang.reflect.Method.invoke(Method.java:521)
09-07 17:15:13.801: E/AndroidRuntime(812):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-07 17:15:13.801: E/AndroidRuntime(812):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-07 17:15:13.801: E/AndroidRuntime(812):  at dalvik.system.NativeStart.main(Native Method)
09-07 17:15:13.801: E/AndroidRuntime(812): Caused by: java.lang.ClassCastException: android.widget.TextView
09-07 17:15:13.801: E/AndroidRuntime(812):  at com.example.intent.Activity1.addListenerOnButton(Activity1.java:22)
09-07 17:15:13.801: E/AndroidRuntime(812):  at com.example.intent.Activity1.onCreate(Activity1.java:17)
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-07 17:15:13.801: E/AndroidRuntime(812):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
09-07 17:15:13.801: E/AndroidRuntime(812):  ... 11 more
09-07 17:20:13.841: I/Process(812): Sending signal. PID: 812 SIG: 9
09-07 17:24:50.690: D/AndroidRuntime(840): Shutting down VM
09-07 17:24:50.690: W/dalvikvm(840): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
09-07 17:24:50.710: E/AndroidRuntime(840): FATAL EXCEPTION: main
09-07 17:24:50.710: E/AndroidRuntime(840): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.intent/com.example.intent.Activity1}: java.lang.ClassCastException: android.widget.TextView
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.os.Looper.loop(Looper.java:123)
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.app.ActivityThread.main(ActivityThread.java:4627)
09-07 17:24:50.710: E/AndroidRuntime(840):  at java.lang.reflect.Method.invokeNative(Native Method)
09-07 17:24:50.710: E/AndroidRuntime(840):  at java.lang.reflect.Method.invoke(Method.java:521)
09-07 17:24:50.710: E/AndroidRuntime(840):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
09-07 17:24:50.710: E/AndroidRuntime(840):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
09-07 17:24:50.710: E/AndroidRuntime(840):  at dalvik.system.NativeStart.main(Native Method)
09-07 17:24:50.710: E/AndroidRuntime(840): Caused by: java.lang.ClassCastException: android.widget.TextView
09-07 17:24:50.710: E/AndroidRuntime(840):  at com.example.intent.Activity1.addListenerOnButton(Activity1.java:22)
09-07 17:24:50.710: E/AndroidRuntime(840):  at com.example.intent.Activity1.onCreate(Activity1.java:17)
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-07 17:24:50.710: E/AndroidRuntime(840):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
09-07 17:24:50.710: E/AndroidRuntime(840):  ... 11 more

最佳答案

你错了

  android:name="activity_activity1"
  android:name="activity_activity2"

使用此代码

<activity
    android:name=".Activity1"
    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=".Activity2"
    android:label="@string/app_name">
</activity>

关于android - Android 手机上未安装应用程序，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18672657/