Android Handler简单示例

package com.firstapp.foo.firstapp;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

import java.util.Date;

public class ThreadDemoActivity extends AppCompatActivity {
private static final String TAG = "foo";
private ProgressBar bar;
private Button btnStartThread;
private TextView tvMsg;

private Handler handler;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

handler = new MyHandler();
setContentView(R.layout.activity_thread_demo);
bar = (ProgressBar)findViewById(R.id.progressBar);
btnStartThread = (Button)findViewById(R.id.btnStartThread);
tvMsg = (TextView)findViewById(R.id.tvMsg);

btnStartThread.setOnClickListener(v -> {
new Thread(()->{
for (int i=0; i< 100; i++){
bar.setProgress(i);
try {
Thread.sleep(30);
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.i(TAG, "Thread Info:" + i);
}

Bundle bundle = new Bundle();
bundle.putString("msg","你好");
// other ...
Message message = handler.obtainMessage();
message.what = 2;
message.setData(bundle);
handler.sendMessage(message);

/* 若消息除消息码外,无附加参数，则下面一句更简便 */
//handler.sendEmptyMessage(2);
}).start();
});
}

class MyHandler extends  Handler {
@Override
public void handleMessage(Message msg) {
switch (msg.what){
case 2:
Bundle data = msg.getData();
String txt = data.getString("msg");

tvMsg.setText(txt + ", 线程完成:" + new Date().toString() );
break;
}
}
}
}