测试精灵代码我收到以下错误：
FATAL EXCEPTION: main
Process: marti.sprite1app, PID: 2149
java.lang.RuntimeException: Unable to start activity ComponentInfo{marti.sprite1app/marti.sprite1app.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.support.v7.widget.Toolbar.getTitle()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
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:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.CharSequence android.support.v7.widget.Toolbar.getTitle()' on a null object reference
at android.support.v7.widget.ToolbarWidgetWrapper.<init>(ToolbarWidgetWrapper.java:98)
at android.support.v7.widget.ToolbarWidgetWrapper.<init>(ToolbarWidgetWrapper.java:91)
at android.support.v7.app.ToolbarActionBar.<init>(ToolbarActionBar.java:73)
at android.support.v7.app.AppCompatDelegateImplV7.setSupportActionBar(AppCompatDelegateImplV7.java:205)
at android.support.v7.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:99)
at marti.sprite1app.MainActivity.onCreate(MainActivity.java:19)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
我试图显示一个精灵并在屏幕上显示它，更改了该课程的视图＆＃34; vistaPrincipalJuego＆＃34;。 对不起，英语不是很好。
MainActivity：
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new VistaPrincipalJuego(this));
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
线程子进程：
public class SubprocesoPrincipal extends Thread {
private boolean finJuego;
private SurfaceHolder surfaceHolder;
private VistaPrincipalJuego vistaJuego;
public SubprocesoPrincipal (SurfaceHolder surfaceHolder, VistaPrincipalJuego vista) {
super();
this.surfaceHolder = surfaceHolder;
this.vistaJuego = vista;
}
public void setFinJuego(boolean fj) {
this.finJuego = fj;
}
public void run() {
Canvas lienzo = null;
while (!finJuego) {
try {
lienzo = this.surfaceHolder.lockCanvas();
synchronized (surfaceHolder) {
this.vistaJuego.draw(lienzo);
}
} finally {
if (lienzo != null) {
surfaceHolder.unlockCanvasAndPost(lienzo);
}
}
}
}
}
类扩展了SurfaceView：
public class VistaPrincipalJuego extends SurfaceView implements SurfaceHolder.Callback {
private SubprocesoPrincipal buclePrincipal;
public VistaPrincipalJuego(Context context) {
super(context);
buclePrincipal = new SubprocesoPrincipal(getHolder(), this);
getHolder().addCallback(this);
setFocusable(true);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
this.buclePrincipal.setFinJuego(false);
this.buclePrincipal.start();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean repite = true;
while (repite) {
try {
buclePrincipal.join();
repite = false;
} catch (InterruptedException e) {
}
}
}
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
if (event.getY() > getHeight() - 50) {
buclePrincipal.setFinJuego(true);
((Activity) getContext()).finish();
}
}
return super.onTouchEvent(event);
}
protected void onDraw(Canvas lienzo) {
lienzo.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.mario), 10, 10, null);
}
}
答案 0 :(得分：0)
简单的决定 - 尝试删除所有这些示例代码：
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});