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public class RandomNameActivity extends AppCompatActivity {private TextView tvName;private Button mButton;private String[] names = {"周星驰", "成龙", "李连杰", "叶问", "甄子丹","刘德华", "贾静雯", "吴孟达", "萧十一郎", "小李飞刀"};/*** 是否开始，0-否，1-是*/private int isStart;private Handler mHandler;private Timer mTimer = new Timer();@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_random_name);tvName = findViewById(R.id.tv_name);mButton = findViewById(R.id.btn_random);mButton.setText("开始");mHandler = new Handler(new InnerCallback());mButton.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {if (isStart == 0) {start();} else {stop();}}});}private void start() {isStart = 1;mButton.setText("开始");mTimer.schedule(new TimerTask() {int max = names.length;int min = 0;@Overridepublic void run() {if (isStart == 1) {int num = (int) Math.round(Math.random() * (max - min) + min);if (num >= max) {num--;}//通过Message.obtain构造一个message，并通过Handler发送mHandler.sendMessage(Message.obtain(mHandler, num));}}}, 0, 500);}private void stop() {isStart = 0;mButton.setText("停止");mTimer.cancel();}private class InnerCallback implements Handler.Callback {@Overridepublic boolean handleMessage(Message msg) {//这里接收到sendMessage发送过来的消息，当前线程为UI线程int index = msg.what;tvName.setText(names[index]);return true;}}@Overrideprotected void onDestroy() {mHandler.removeCallbacksAndMessages(null);mTimer.cancel();super.onDestroy();}
}