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首先加载Drawable,在onMeasure设置好其区域大小,
然后使用canvas.clipRect绘图
public class ProgressView extends ImageView {
private Drawable maskDraw;
/**
* 加载的进度 0-100
*/
private int mProcess = 20;
public ProgressView(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() * getProcess() / 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 getProcess() {
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();
}
}
使用方法
public class ProgressActivity extends Activity {
private ProgressView piv;
private int pivDeep = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_progressview);
piv = (ProgressView) 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);
try {
Thread.sleep(200);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
};
}.start();
break;
default:
break;
}
}
};
}
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