利用Handler来更新android的UI (2)
16lz
2022-04-06
利用Handler来更新android的UI (2)
文字程序很简单,一个View,一个Activity,利用handler和postInvalidate()更新UI。
程序效果是一个蓝色的正方形向右移出屏幕。
package com.ray.test;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
public class TestHandler extends Activity {
private MyView myView;
private Handler mHandler;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
myView = new MyView(this);
mHandler = new Handler();
mHandler.post(update);
setContentView(myView);
}
private Runnable update = new Runnable() {
public void run() {
myView.update();
mHandler.postDelayed(update, 5);
}
};
class MyView extends View{
private float x = 0f;
public MyView(Context context) {
super(context);
}
public void update(){
postInvalidate();
}
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
x+=1;
Paint mPaint = new Paint();
mPaint.setColor(Color.BLUE);
canvas.drawRect(x, 40, x+40, 80, mPaint);
}
}
文字程序很简单,一个View,一个Activity,利用handler和postInvalidate()更新UI。
程序效果是一个蓝色的正方形向右移出屏幕。
package com.ray.test;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
public class TestHandler extends Activity {
private MyView myView;
private Handler mHandler;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
myView = new MyView(this);
mHandler = new Handler();
mHandler.post(update);
setContentView(myView);
}
private Runnable update = new Runnable() {
public void run() {
myView.update();
mHandler.postDelayed(update, 5);
}
};
class MyView extends View{
private float x = 0f;
public MyView(Context context) {
super(context);
}
public void update(){
postInvalidate();
}
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
x+=1;
Paint mPaint = new Paint();
mPaint.setColor(Color.BLUE);
canvas.drawRect(x, 40, x+40, 80, mPaint);
}
}
更多相关文章
- Android中当前时间的动态显示
- android自动更新软件版本
- Android(安卓)常见问题收集 (持续更新)
- Android中利用Intent传递数据到另一个页面
- Android(安卓)利用TwinklingRefreshLayout 实现下拉效果
- android更新UI的几种方法
- android延时更新UI
- android handle ui 更新
- Android在子线程中更新UI(二)