RevealView

记录一个demo，自己很喜欢 ©程序亦非猿 InstalMaterial学习笔记之Reveal效果 ，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();
}
@Override
protected 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>