<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="设置一个整数"/>
<EditText
android:id="@+id/et_num"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="计算结果为"/>
<TextView
android:id="@+id/tv_result"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="@+id/btn_start"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="开始计算"/>
</LinearLayout>
public class MainActivity extends AppCompatActivity {
private static final int NUMBER = 1;
private static final int RESULT = 0;
private MyThread myThread;
private TextView tvResult;
private EditText etNum;
//主线程Handler
private Handler mainHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
//处理Message,运行在主线程,可以修改界面元素
switch (msg.what) {
case RESULT:
long res = (long) msg.obj;
tvResult.setText(res + "");
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvResult = findViewById(R.id.tv_result);
etNum = findViewById(R.id.et_num);
//创建子线程
myThread = new MyThread();
myThread.start();
Button button = findViewById(R.id.btn_start);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String str = etNum.getText().toString();
//向子线程发送数据
Message message = new Message();
message.what = NUMBER;
message.obj = Integer.parseInt(str);
workHandler.sendMessage(message);
}
});
}
//子线程的Handler
private Handler workHandler;
private class MyThread extends Thread {
@Override
public void run() {
super.run();
//子线程中使用Handler要手动开启Looper
Looper.prepare();
workHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
//处理来自主线程的数据
switch (msg.what){
case NUMBER:
long res = fib((int)msg.obj);
//发送Message
Message message = new Message();
//添加数据
message.obj = res;
//添加标识
message.what = RESULT;
mainHandler.sendMessage(message);
break;
}
}
};
Looper.loop();
//不能直接在子线程中修改UI
// tvResult.setText(res+"");
}
}
private long fib(int n) {
if (n == 1) {
return 1;
} else if (n == 2) {
return 1;
} else {
return fib(n - 1) + fib(n - 2);
}
}
}
主线程和子线程之间传递消息
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转载自blog.csdn.net/guoguo_up/article/details/83214271
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