记录一个demo，自己很喜欢 ，坚持不懈向大神学习

。。

先看效果

再看代码

<pre>

package github.alex.revealview;

import android.animation.Animator;

import android.animation.AnimatorListenerAdapter; import android.animation.ObjectAnimator; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.util.AttributeSet; import android.view.View; import android.view.animation.AccelerateInterpolator; import android.view.animation.Interpolator;

/**

* Created by Miroslaw Stanek on 18.01.15. */ public class RevealView extends View { /**填充色*/ private Paint fillPaint; /**初始化状态*/ public static final int state_not_started = 0; /**揭露动画开始*/ public static final int state_fill_started = 1; /**揭露动画完成*/ public static final int state_finished = 2; private int state = state_not_started; /**开始的X坐标，相对于手机屏幕，不包括状态栏*/ private int startLocationX; /**开始的Y坐标，相对于手机屏幕，不包括状态栏*/ private int startLocationY; /**当前揭露动画的半径*/ private int currentRadius; private ObjectAnimator revealAnimator; private Interpolator interpolator = null; private OnStateChangeListener onStateChangeListener; /**揭露动画的时间*/ private int fillTime; public RevealView(Context context) { super(context); } public RevealView(Context context, AttributeSet attrs) { super(context, attrs); initView(); }

private void initView() {    fillPaint = new Paint();    fillPaint.setStyle(Paint.Style.FILL);    fillPaint.setColor(Color.WHITE);    interpolator = new AccelerateInterpolator();    fillTime = 400;}public void setFillColor(int color) {    fillPaint.setColor(color);}public void startFromLocation(int[] tapLocationOnScreen) {    changeState(state_fill_started);    startLocationX = tapLocationOnScreen[0];    startLocationY = tapLocationOnScreen[1];    /\*此时 利用反射机制 自动调用setCurrentRadius方法，并将参数传递过去\*/    revealAnimator = ObjectAnimator.ofInt(this, "currentRadius", 0, getWidth() + getHeight()).setDuration(fillTime);    revealAnimator.setInterpolator(interpolator);    revealAnimator.addListener(new MyAnimatorListenerAdapter());    revealAnimator.start();}private void changeState(int state) {    if (this.state == state) {        return;    }    this.state = state;    if (onStateChangeListener != null) {        onStateChangeListener.onStateChange(state);    }}public void setCurrentRadius(int radius) {    this.currentRadius = radius;    invalidate();}@Overrideprotected void onDraw(Canvas canvas) {    if (state == state_finished) {        canvas.drawRect(0, 0, getWidth(), getHeight(), fillPaint);    } else {        canvas.drawCircle(startLocationX, startLocationY, currentRadius, fillPaint);    }}private final class MyAnimatorListenerAdapter extends AnimatorListenerAdapter{    @Override    public void onAnimationEnd(Animator animation) {        changeState(state_finished);    }}public void setOnStateChangeListener(OnStateChangeListener onStateChangeListener) {    this.onStateChangeListener = onStateChangeListener;}public static interface OnStateChangeListener {    void onStateChange(int state);}

}

</pre>

<pre>

public class NewActivity extends AppCompatActivity {

private RevealView revealView; private int[] location; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_new); location = getIntent().getExtras().getIntArray("location"); initView(); } private void initView() { findViewById(R.id.bt_5).setOnClickListener(new MyOnClickListener()); revealView = (RevealView) findViewById(R.id.rv); revealView.setVisibility(View.VISIBLE); revealView.setFillColor(Color.parseColor("#BBFF5722")); /*当一个视图树将要绘制时，所要调用的回调函数的接口类*/ revealView.getViewTreeObserver().addOnPreDrawListener(new MyOnPreDrawListener()); revealView.setOnStateChangeListener(new MyOnStateChangeListener()); }

private final class MyOnClickListener implements View.OnClickListener {    @Override    public void onClick(View v) {        finish();    }}private final class MyOnStateChangeListener implements RevealView.OnStateChangeListener {    @Override    public void onStateChange(int state) {        if (state == RevealView.state_finished) {            revealView.setVisibility(View.GONE);        }    }}private final class MyOnPreDrawListener implements ViewTreeObserver.OnPreDrawListener {    @Override    public boolean onPreDraw() {        //必须remove掉 不然会重复调用        revealView.getViewTreeObserver().removeOnPreDrawListener(this);        revealView.startFromLocation(location);        return false;    }}

}

</pre>