我已经查看了所有与此相关的讨论和线程,但还是无法使它工作。我有一个简单的计时器,可以更新文本视图(在下面的示例中为mTimeTextField)。mUpdateTimeTask运行方法被正确执行(每秒一次),但UI / 文本字段未被更新。
我基于此处找到的信息编写了代码:
我基于此处找到的信息编写了代码:
http://android-developers.blogspot.com/2007/11/stitch-in-time.html http://developer.android.com/resources/articles/timed-ui-updates.html
这里是代码:
package com.something.handlertest;
import com.something.handlertest.R;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.SystemClock;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Test extends Activity {
private Handler mHandler = new Handler();
private int labelNo = 0;
private long currTime = 0L;
private long mStartTime = 0L;
TextView mTimeTextField;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mTimeTextField = (TextView)findViewById(R.id.timeTextFieldl);
Button startButton = (Button)findViewById(R.id.start_button);
startButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (mStartTime == 0L) {
mStartTime = System.currentTimeMillis();
mHandler.removeCallbacks(mUpdateTimeTask);
mHandler.postDelayed(mUpdateTimeTask, 100);
}
}
});
}
private Runnable mUpdateTimeTask = new Runnable() {
public void run() {
final long start = mStartTime;
//long millis = SystemClock.uptimeMillis() - start;
long millis = SystemClock.uptimeMillis();
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
//setContentView(mTimeTextField); This will blow up if I use it
if (seconds < 10) {
mTimeTextField.setText("" + minutes + ":0" + seconds);
} else {
mTimeTextField.setText("" + minutes + ":" + seconds);
}
//mHandler.postAtTime(this,
// start + (((minutes * 60) + seconds + 1) * 1000));
mHandler.postAtTime(this, 1000);
}
};
}
根据一些建议,我尝试添加了:
setContentView(mTimeLabel);
但这会导致崩溃,抱怨视图没有父视图。顺便说一下,我确实有一个:
setContentView(R.layout.main);
在我的onCreate()
中调用。