我正在开发一款游戏应用。我正在使用Android Studio进行编码，我决定通过一个教程来帮助我理解MotionEvents，Threads等。当我完成教程时，代码的想法是允许我对屏幕顶部的任何地方施加压力LogCat假设给我x和y坐标，如果我点击屏幕底部的任何地方，应用程序应该停止。现在，问题是当你点击应用程序时，游戏意外停止工作，我相信问题是因为教程是在2010年制作的，并且较新的Android版本与它有些冲突，但我有知道从哪里开始的麻烦。我将展示代码以及尝试运行应用程序时出现的任何错误：
package com.example.dsdude.gameexample;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class MainGamePanel extends SurfaceView implements SurfaceHolder.Callback {
private MainThread thread;
private static final String TAG = MainGamePanel.class.getSimpleName();
public MainGamePanel(Context context) {
super(context);
//adding the callback (this) to the surface holder to intercept events
getHolder().addCallback(this);
//create the game loop thread
thread = new MainThread(getHolder(), this);
//make the GamePanel focusable so it can handle events
setFocusable(true);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
thread.setRunning(true);
thread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
Log.d(TAG, "Surface is being destroyed");
boolean retry = true;
while (retry) {
try {
thread.setRunning(false);
thread.join();
((Activity)getContext()).finish();
} catch (InterruptedException e) {
e.printStackTrace();
// try again shutting down the thread
}
retry = false;
}
Log.d(TAG, "Thread was shut down cleanly");
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
if (event.getY() > getHeight() - 50) {
thread.setRunning(false);
((Activity)getContext()).finish();
} else {
Log.d(TAG, "Coords: x=" + event.getX() + ",y=" + event.getY());
}
}
return super.onTouchEvent(event);
}
@Override
protected void onDraw(Canvas canvas) {
}
}
package com.example.dsdude.gameexample;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.view.WindowManager;
public class DroidzActivity extends Activity {
/**
* Called when the activity is first created.
*/
private static final String TAG = DroidzActivity.class.getSimpleName();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// requesting to turn the title OFF
requestWindowFeature(Window.FEATURE_NO_TITLE);
// making it full screen
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
// set our MainGamePanel as the View
setContentView(new MainGamePanel(this));
Log.d(TAG, "View added");
}
@Override
protected void onDestroy() {
Log.d(TAG, "Destroying...");
super.onDestroy();
}
@Override
protected void onStop() {
Log.d(TAG, "Stopping...");
super.onStop();
}
}
package com.example.dsdude.gameexample;
import android.util.Log;
import android.view.SurfaceHolder;
public class MainThread extends Thread {
private static final String TAG = MainThread.class.getSimpleName();
private SurfaceHolder surfaceHolder;
private MainGamePanel gamePanel;
//flag to hold game state
private boolean running;
public void setRunning(boolean running) {
this.running = running;
}
@Override
public void run() {
long tickCount = 0L;
Log.d(TAG, "Starting game loop");
while (running) {
tickCount++;
//update game state
//render state to the screen
}
Log.d(TAG, "Game loop executed " + tickCount + " times");
}
public MainThread(SurfaceHolder surfaceHolder, MainGamePanel gamePanel) {
super();
this.surfaceHolder = surfaceHolder;
this.gamePanel = gamePanel;
}
}
这是logcat：
02-18 16:08:01.091 1065-1065/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.dsdude.gameexample, PID: 1065
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.dsdude.gameexample/com.example.dsdude.gameexample.MainGamePanel}: java.lang.InstantiationException: class com.example.dsdude.gameexample.MainGamePanel has no zero argument constructor
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2999)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3263)
at android.app.ActivityThread.access$1000(ActivityThread.java:197)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1687)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6897)
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:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
Caused by: java.lang.InstantiationException: class com.example.dsdude.gameexample.MainGamePanel has no zero argument constructor
at java.lang.Class.newInstance(Class.java:1681)
at android.app.Instrumentation.newActivity(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2989)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3263)
at android.app.ActivityThread.access$1000(ActivityThread.java:197)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1687)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6897)
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:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
Caused by: java.lang.NoSuchMethodException: <init> []
at java.lang.Class.getConstructor(Class.java:531)
at java.lang.Class.getDeclaredConstructor(Class.java:510)
at java.lang.Class.newInstance(Class.java:1679)
at android.app.Instrumentation.newActivity(Instrumentation.java:1080)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2989)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3263)
at android.app.ActivityThread.access$1000(ActivityThread.java:197)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1687)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6897)
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:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
02-18 16：11：34.411 1065-1065 / com.example.dsdude.gameexample I / Process：发送信号。 PID：1065 SIG：9
任何帮助都会受到赞赏，我只想知道我应该采用什么方向来理解问题所在。该程序编译得很好，没有错误，但MainGamePanel.java必须出错，因为它无法实例化活动。