以下代码来自Beginning Android 3,第20章。当手机旋转时,将创建一个新活动并调用onStart(),因此调用bar.setProgress(0)。但是,我没有看到酒吧的进展又回到了开始阶段。为什么不呢?
public class HandlerDemo extends Activity {
ProgressBar bar;
Handler handler=new Handler() {
@Override
public void handleMessage(Message msg) {
bar.incrementProgressBy(5);
}
};
AtomicBoolean isRunning=new AtomicBoolean(false);
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
bar=(ProgressBar)findViewById(R.id.progress);
}
public void onStart() {
super.onStart();
bar.setProgress(0);
Thread background=new Thread(new Runnable() {
public void run() {
try {
for (int i=0;i<20 && isRunning.get();i++) {
Thread.sleep(1000);
handler.sendMessage(handler.obtainMessage());
}
} catch (Throwable t) {
// just end the background thread
}
}
});
isRunning.set(true);
background.start();
}
public void onStop() {
super.onStop();
isRunning.set(false);
}
}
答案 0 :(得分:1)
尝试使用此代码
@Override
protected void onPause() {
super.onPause();
isRunning.set(false);
bar.setProgress(0);
}