Question

我的应用程序应该在按钮单击时将活动更改为其他活动，但它会崩溃。我有两个.java文件和两个.xml文件。以下是红色错误消息。谢谢

09-28 01:16:35.020: D/AndroidRuntime(1606): Shutting down VM
09-28 01:16:35.020: W/dalvikvm(1606): threadid=1: thread exiting with uncaught exception (group=0xb3b04ba8)
09-28 01:16:35.090: E/AndroidRuntime(1606): FATAL EXCEPTION: main
09-28 01:16:35.090: E/AndroidRuntime(1606): Process: com.example.startscreenapp, PID: 1606
09-28 01:16:35.090: E/AndroidRuntime(1606): android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.startscreenapp/com.example.startscreenapp.PlayGame}; have you declared this activity in your AndroidManifest.xml?
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1628)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1424)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.app.Activity.startActivityForResult(Activity.java:3424)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.app.Activity.startActivityForResult(Activity.java:3385)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at com.example.startscreenapp.StartScreen.startGame(StartScreen.java:46)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at com.example.startscreenapp.StartScreen.access$0(StartScreen.java:41)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at com.example.startscreenapp.StartScreen$1.onClick(StartScreen.java:26)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.view.View.performClick(View.java:4438)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.view.View$PerformClick.run(View.java:18422)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.os.Handler.handleCallback(Handler.java:733)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.os.Handler.dispatchMessage(Handler.java:95)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.os.Looper.loop(Looper.java:136)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at android.app.ActivityThread.main(ActivityThread.java:5017)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at java.lang.reflect.Method.invokeNative(Native Method)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at java.lang.reflect.Method.invoke(Method.java:515)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
09-28 01:16:35.090: E/AndroidRuntime(1606):     at dalvik.system.NativeStart.main(Native Method)
09-28 01:21:35.230: I/Process(1606): Sending signal. PID: 1606 SIG: 9

我有两个.java文件和两个.xml文件。

StartScreen.java

package com.example.startscreenapp;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class StartScreen extends Activity {
    private static final int PLAY_GAME = 1010;
    private TextView tv;
    private int meaningOfLife = 42;
    private String userName = "Douglas Adams";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.startscreen);
        //Display initial values
        tv.setText(userName + ":" + meaningOfLife);
        //Set up button listener
        Button startButton = (Button) findViewById(R.id.play_game);
        startButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                startGame();
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == PLAY_GAME && resultCode == RESULT_OK) {
            meaningOfLife = data.getExtras().getInt("returnInt");
            userName = data.getExtras().getString("returnStr");
            //Show it has changed
            tv.setText(userName + ":" + meaningOfLife);
        }
            super.onActivityResult(requestCode, resultCode, data);
    }

    private void startGame() {
        Intent launchGame = new Intent(this, PlayGame.class);
        //passing information to launched activity
        launchGame.putExtra("meaningOfLife", meaningOfLife);
        launchGame.putExtra("userName", userName);
        startActivityForResult(launchGame, PLAY_GAME);
    }
}

PlayGame.java

package com.example.startscreenapp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class PlayGame extends Activity {
    private TextView tv2;
    int answer;
    String author;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.game);
        tv2 = (TextView) findViewById(R.id.game_text);
        //reading information passed to this activity
        //Get the intent that started this activity
        Intent i = getIntent();
        //returns -1 if not initialized by calling activity
        answer = i.getIntExtra("meaningOfLife", -1);
        //returns [] if not initialized by calling activity
        author = i.getStringExtra("userName");
        tv2.setText(author + ":" + answer);
        //Change values for an example of return
        answer = answer - 41;
        author = author + " Jr.";
        //Set up button listener
        Button startButton = (Button) findViewById(R.id.end_game);
        startButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                //Return information to calling activity
                Intent i = getIntent();
                i.putExtra("returnInt", answer);
                i.putExtra("returnStr", author);
                setResult(RESULT_OK, i);
                finish();
            }
        });
    }
}

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="${relativePackage}.${activityClass}" >

    <TextView
        android:id="@+id/startscreen"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="115dp"
        android:layout_marginTop="164dp"
        android:text="TextView" />

    <Button
        android:id="@+id/play_game"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/startscreen"
        android:layout_below="@+id/startscreen"
        android:layout_marginTop="64dp"
        android:text="Start" />

</RelativeLayout>

game.xml

<?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/game_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView" />

    <Button
        android:id="@+id/end_game"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button" />

</LinearLayout>

Answer 1

您应该在AndroidManifest.xml中声明所有活动，包括StartScreen和PlayGame。

例如，添加

<activity android:name="com.example.startscreenapp.PlayGame"></activity>

进入AndroidManifest.xml

Answer 2

正如您的错误所说，您必须在清单中声明活动。

<activity 
    android:name="com.example.startscreenapp.PlayGame">
</activity>

应用程序按下按钮时崩溃

2 个答案: