Android 实现模糊半透明效果的简单实现

import android.animation.Animator; import android.animation.AnimatorSet; import android.animation.ObjectAnimator; import android.animation.ValueAnimator; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.view.animation.OvershootInterpolator; import android.widget.ImageView;

import java.util.Random;

public class MainActivity extends AppCompatActivity {

private BlurringView mBlurringView;

@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);

mBlurringView = (BlurringView) findViewById(R.id.blurring_view); View blurredView = findViewById(R.id.blurred_view);

//给出了模糊视图并刷新模糊视图。

mBlurringView.setBlurredView(blurredView); mBlurringView.invalidate();

}

private ValueAnimator.AnimatorUpdateListener listener = new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator animation) { mBlurringView.invalidate(); } }; }

import android.content.Context; import android.content.res.Resources; import android.content.res.TypedArray; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.drawable.ColorDrawable; import android.renderscript.Allocation; import android.renderscript.Element; import android.renderscript.RenderScript; import android.renderscript.ScriptIntrinsicBlur; import android.util.AttributeSet; import android.view.View;

/** * A custom view for presenting a dynamically blurred version of another view's content. *

* Use {@link #setBlurredView(View)} to set up the reference to the view to be blurred. * After that, call {@link #invalidate()} to trigger blurring whenever necessary. */ public class BlurringView extends View {

public BlurringView(Context context) { this(context, null); }

public BlurringView(Context context, AttributeSet attrs) { super(context, attrs);

final Resources res = getResources(); final int defaultBlurRadius = res.getInteger(R.integer.default_blur_radius); final int defaultDownsampleFactor = res.getInteger(R.integer.default_downsample_factor); final int defaultOverlayColor = res.getColor(R.color.default_overlay_color);

initializeRenderScript(context);

TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.PxBlurringView); setBlurRadius(a.getInt(R.styleable.PxBlurringView_blurRadius, defaultBlurRadius)); setDownsampleFactor(a.getInt(R.styleable.PxBlurringView_downsampleFactor, defaultDownsampleFactor)); setOverlayColor(a.getColor(R.styleable.PxBlurringView_overlayColor, defaultOverlayColor)); a.recycle(); }

public void setBlurredView(View blurredView) { mBlurredView = blurredView; }

@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (mBlurredView != null) { if (prepare()) { // If the background of the blurred view is a color drawable, we use it to clear // the blurring canvas, which ensures that edges of the child views are blurred // as well; otherwise we clear the blurring canvas with a transparent color. if (mBlurredView.getBackground() != null && mBlurredView.getBackground() instanceof ColorDrawable) { mBitmapToBlur.eraseColor(((ColorDrawable) mBlurredView.getBackground()).getColor()); } else { mBitmapToBlur.eraseColor(Color.TRANSPARENT); }

mBlurredView.draw(mBlurringCanvas); blur();

canvas.save(); canvas.translate(mBlurredView.getX() - getX(), mBlurredView.getY() - getY()); canvas.scale(mDownsampleFactor, mDownsampleFactor); canvas.drawBitmap(mBlurredBitmap, 0, 0, null); canvas.restore(); } canvas.drawColor(mOverlayColor); } }

public void setBlurRadius(int radius) { mBlurScript.setRadius(radius); }

public void setDownsampleFactor(int factor) { if (factor <= 0) { throw new IllegalArgumentException("Downsample factor must be greater than 0."); }

if (mDownsampleFactor != factor) { mDownsampleFactor = factor; mDownsampleFactorChanged = true; } }

public void setOverlayColor(int color) { mOverlayColor = color; }

private void initializeRenderScript(Context context) { mRenderScript = RenderScript.create(context); mBlurScript = ScriptIntrinsicBlur.create(mRenderScript, Element.U8_4(mRenderScript)); }

protected boolean prepare() { final int width = mBlurredView.getWidth(); final int height = mBlurredView.getHeight();

if (mBlurringCanvas == null || mDownsampleFactorChanged || mBlurredViewWidth != width || mBlurredViewHeight != height) { mDownsampleFactorChanged = false;

mBlurredViewWidth = width; mBlurredViewHeight = height;

int scaledWidth = width / mDownsampleFactor; int scaledHeight = height / mDownsampleFactor;

// The following manipulation is to avoid some RenderScript artifacts at the edge. scaledWidth = scaledWidth - scaledWidth % 4 + 4; scaledHeight = scaledHeight - scaledHeight % 4 + 4;

if (mBlurredBitmap == null || mBlurredBitmap.getWidth() != scaledWidth || mBlurredBitmap.getHeight() != scaledHeight) { mBitmapToBlur = Bitmap.createBitmap(scaledWidth, scaledHeight, Bitmap.Config.ARGB_8888); if (mBitmapToBlur == null) { return false; }

mBlurredBitmap = Bitmap.createBitmap(scaledWidth, scaledHeight, Bitmap.Config.ARGB_8888); if (mBlurredBitmap == null) { return false; } }

mBlurringCanvas = new Canvas(mBitmapToBlur); mBlurringCanvas.scale(1f / mDownsampleFactor, 1f / mDownsampleFactor); mBlurInput = Allocation.createFromBitmap(mRenderScript, mBitmapToBlur, Allocation.MipmapControl.MIPMAP_NONE, Allocation.USAGE_SCRIPT); mBlurOutput = Allocation.createTyped(mRenderScript, mBlurInput.getType()); } return true; }

protected void blur() { mBlurInput.copyFrom(mBitmapToBlur); mBlurScript.setInput(mBlurInput); mBlurScript.forEach(mBlurOutput); mBlurOutput.copyTo(mBlurredBitmap); }

@Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); if (mRenderScript != null) { mRenderScript.destroy(); } }

private int mDownsampleFactor; private int mOverlayColor;

private View mBlurredView; private int mBlurredViewWidth, mBlurredViewHeight;

private boolean mDownsampleFactorChanged; private Bitmap mBitmapToBlur, mBlurredBitmap; private Canvas mBlurringCanvas; private RenderScript mRenderScript; private ScriptIntrinsicBlur mBlurScript; private Allocation mBlurInput, mBlurOutput;

}