自定义加载进度动画

一、还是老惯例，不多说，先上图



二、创建一个类继承View

Ⅰ、实现带参数的构造方法ProgressImage(Context context, AttributeSet attrs)

Ⅱ、重写onDraw(Canvas canvas)方法

Ⅲ、重写onMeasure(int widthMeasureSpec, int heightMeasureSpec)方法

package net.dxs.baihedemo;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.ImageView;

public class ProgressImage extends ImageView {

private Drawable maskDraw;

/**
* 加载的进度
* 0-100
*/
private int mProcess = 20;

public ProgressImage(Context context, AttributeSet attrs) {
super(context, attrs);
maskDraw = context.getResources().getDrawable(R.drawable.red_bg);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//保存当前画笔的状态
canvas.save();

int topline = (int) (getHeight() - getHeight() * getmProcess() / 100);
/*
* canvas 剪切出一个区域，使在这个区域里面的内容是有效的，区域之外是无效的。
*/
canvas.clipRect(0, topline, getWidth(), getHeight());

maskDraw.draw(canvas);

//恢复到之前保存的状态
canvas.restore();
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
maskDraw.setBounds(0, 0, getWidth(), getHeight());
}

public float getmProcess() {
return mProcess;
}

/**
* 设置新的进度以后，自动刷新
*/
public void setProgress(int mProcess) {
if (mProcess > 100) {
this.mProcess = 100;
}
if (mProcess < 0) {
this.mProcess = 0;
}

this.mProcess = mProcess;
invalidate();
}

}


三、调用

使用handler实现回调

package net.dxs.baihedemo;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;

public class ProImageActivity extends Activity {

private ProgressImage piv;

private int pivDeep = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

setContentView(R.layout.pro_image_test);

piv = (ProgressImage) findViewById(R.id.my_pro_iv);

handler.sendEmptyMessage(2);

}

private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 1:
piv.setProgress(pivDeep);
break;
case 2:
new Thread() {
public void run() {
while (true) {
pivDeep = (pivDeep + 5) % 100;
handler.sendEmptyMessage(1);
SystemClock.sleep(200);
}
};
}.start();
break;
}
}
};
}


四、布局代码

添加自定义的view

<?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:gravity="center"
android:orientation="vertical" >

<net.dxs.baihedemo.ProgressImage
android:id="@+id/my_pro_iv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/gray_bg" />

</LinearLayout>

到这里就搞定了，
主要使用了canvas.clipRect剪切方法