簡書: http://www.lxweimin.com/p/89abe37bc8f2
效果
snow.gif
說明
之前使用的是一個第三方提供的fallingView,發(fā)現(xiàn)他繼承的是View,
而View更新界面要放在主線程,像這種一直有動畫效果的View,會在用戶有操作時出現(xiàn)卡頓現(xiàn)象.
不停的繪制動畫效果,SurfaceView應(yīng)該最合適了,更新界面放在一個單獨線程中,不會阻塞主線程
使用SurfaceView注意事項
surfaceview背景默認(rèn)是黑色的,為了讓他背景透明,需要兩步:
- 在構(gòu)造方法中:
setZOrderOnTop(true);
getHolder().setFormat(PixelFormat.TRANSLUCENT);
- 在繪制時:
//獲取canvas畫布
Canvas cancas=holder.lockCanvas();
if(canvas ==null)
return;
canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
代碼
package com.eqdd.yiqidian.widget;
/**
* @author呂志豪 .
* @date 18-3-1 下午4:41.
* Github :https://github.com/lvzhihao100
* E-Mail:1030753080@qq.com
* 簡書 :http://www.lxweimin.com/u/6e525b929aac
*/
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.PixelFormat;
import android.graphics.PorterDuff;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import com.gamerole.fallview.FallObject;
import java.util.ArrayList;
import java.util.List;
import io.reactivex.Observable;
import io.reactivex.schedulers.Schedulers;
public class SurfaceFallView extends SurfaceView implements SurfaceHolder.Callback {
private List<FallObject> fallObjects;
private int viewWidth;
private int viewHeight;
private boolean mStart;
public SurfaceFallView(Context context) {
super(context);
this.init();
}
public SurfaceFallView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
this.init();
}
private void init() {
this.fallObjects = new ArrayList();
getHolder().addCallback(this);
//背景透明第一步
setZOrderOnTop(true);
getHolder().setFormat(PixelFormat.TRANSLUCENT);
}
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int height = this.measureSize(1000, heightMeasureSpec);
int width = this.measureSize(600, widthMeasureSpec);
this.setMeasuredDimension(width, height);
this.viewWidth = width;
this.viewHeight = height;
}
private int measureSize(int defaultSize, int measureSpec) {
int result = defaultSize;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);
if (specMode == MeasureSpec.EXACTLY) {
result = specSize;
} else if (specMode == MeasureSpec.UNSPECIFIED) {
result = Math.min(defaultSize, specSize);
}
return result;
}
public void addFallObject(final FallObject fallObject, final int num) {
//使用post可以保證測量完畢,viewWidth與viewHeight為正確值
post(() -> {
for (int i = 0; i < num; i++) {
fallObjects.add(new FallObject(fallObject.builder, viewWidth, viewHeight));
}
});
}
public boolean onTouchEvent(MotionEvent event) {
return false;
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
mStart = true;
start();
}
private void start() {
Observable.just(1)
.observeOn(Schedulers.newThread())
.subscribe(aLong -> {
while (true) {
if (mStart) {
Canvas canvas = getHolder().lockCanvas();
if (canvas == null)
return;
//背景透明第二步
canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
if (this.fallObjects.size() > 0) {
for (int i = 0; i < this.fallObjects.size(); ++i) {
this.fallObjects.get(i).drawObject(canvas);
}
}
getHolder().unlockCanvasAndPost(canvas);
Thread.sleep(20);
}
}
});
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
/**
* 重寫 onVisibilityChanged() 函數(shù),在控件不可見時停止更新和繪制控件,避免CPU資源浪費:
* @param changedView
* @param visibility
*/
@Override
protected void onVisibilityChanged(View changedView, int visibility) {
super.onVisibilityChanged(changedView, visibility);
mStart = (visibility == VISIBLE);
}
}