导读
1.多线程与ANR
2.Thread类的使用
3.Handler, Looper, MessageQueue
4.主线程与子线程的通信
多线程与ANR
Thread类的使用
基本知识点
扩展Thread类
布局文件 activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.hala.thread.MainActivity">
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Start to work! "
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
MainActivity.java
package com.hala.thread;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
private final String TAG="Thread";
private Button mStartWorkButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mStartWorkButton=(Button) findViewById(R.id.button);
mStartWorkButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//四个线程同时工作
SaleTickets saleTickets1=new SaleTickets(5);
SaleTickets saleTickets2=new SaleTickets(6);
SaleTickets saleTickets3=new SaleTickets(8);
SaleTickets saleTickets4=new SaleTickets(10);
saleTickets1.start();
saleTickets2.start();
saleTickets3.start();
saleTickets4.start();
}
});
}
private class SaleTickets extends Thread{
private int tickets=0;
public SaleTickets(int tickets){
this.tickets=tickets;
}
@Override
public void run() {
super.run();
while (tickets>0){
saleTicket();
}
Log.d(TAG,""+Thread.currentThread().getName()+"sale tickets done!");
}
private void saleTicket(){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
tickets--;
Log.d(TAG,""+Thread.currentThread().getName()+"Saled one ticket, left"+tickets+"tickets!");
}
}
}
显示结果
Runnable接口
⚠️其实Thread类在本质上还是继承了Runnable接口
布局文件不变
MainActivity.java
package com.hala.thread;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
private final String TAG="Thread";
private Button mStartWorkButton;
private SaleTickets SaleTicket;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mStartWorkButton=(Button) findViewById(R.id.button);
mStartWorkButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new Thread(SaleTicket,"队伍一").start();
}
});
SaleTicket=new SaleTickets(10);
}
private class SaleTickets implements Runnable{
private int tickets=0;
public SaleTickets(int tickets){
this.tickets=tickets;
}
@Override
public void run() {
while (tickets>0){
sale();
}
Log.d(TAG,""+Thread.currentThread().getName()+"票卖完了");
}
private void sale(){
tickets--;
Log.d(TAG,""+Thread.currentThread().getName()+"卖了一张票，还剩下："+tickets+" 张票!");
}
}
}
显示结果
Handler, Looper, MessageQueue
总结
主线程与子线程的通信
布局文件
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.hala.thread.MainActivity">
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Start to work! "
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:text="hahaha"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/button" />
</android.support.constraint.ConstraintLayout>
MainActivity.java
package com.hala.thread;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private final String TAG="Thread";
private Button mStartWorkButton;
private TextView mTextView;
private Handler mMainHandler;
private Handler mChildHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTextView=(TextView)findViewById(R.id.text) ;
mStartWorkButton=(Button) findViewById(R.id.button);
mStartWorkButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(mChildHandler!=null) {
Message msg = new Message();
msg.what = 9;
msg.obj = "Emilia Clark";
mChildHandler.sendMessage(msg);
}
}
});
mMainHandler=new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
String fromChildHandler=(String) msg.obj;
mTextView.setText(fromChildHandler);
}
};
new ChildThread().start();
}
private class ChildThread extends Thread{
@Override
public void run() {
super.run();
Looper.prepare();
mChildHandler=new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
Log.d(TAG,"接收到主线程发过来的what="+msg.what);
String fromMainString=(String)msg.obj;
String toMainString= fromMainString+" i v u";
Message message=new Message();
message.obj=toMainString;
if(mMainHandler!=null){
mMainHandler.sendMessage(message);
}
}
};
Looper.loop();
}
}
}
显示结果