华为手机兼容性处理

华为Toast显示

因为华为系统对Toast进行了定制，所以如果两个触发时机非常接近的Toast，华为只会显示一个。例:

Toast.makeText(this, "this is toast 1", Toast.LENGTH_SHORT).show();
Toast.makeText(this, "this is toast 2", Toast.LENGTH_Long).show();

则华为手机只会显示最后一个toast。

背景绘制

最近在做项目的时候，需要给一个Fragment的背景绘制上倾斜的水印，水印的绘制通过自定义drawable，重写draw()方法生成一张drawable，然后用setBackground()设置为背景。

水印生成的代码如下：

public class WarterMarkDrawable extends Drawable {

    Context context;
    String markStr = "";
    int textColor = Color.BLACK;
    int textSize = 30;
    int backgroundColor = Color.WHITE;
    int rotate = -30;
    int alpha = 41;
    int density = 10;
    private Paint paint = new Paint();

    public WarterMarkDrawable(Context context, String watermark) {
        this.context = context;
        this.markStr = watermark;
        this.textColor = ContextCompat.getColor(context, R.color.water_mark_color);
        this.textSize = 42;
        this.backgroundColor = ContextCompat.getColor(context, R.color.background_6_0);
        this.rotate = -20;
        this.density = 7;
    }

    @Override
    public void draw(@NonNull Canvas canvas) {
        int width = getBounds().right + 200;
        int height = getBounds().bottom + 200;
      
        canvas.drawColor(backgroundColor);
        paint.setColor(textColor);
        paint.setAntiAlias(true);
        paint.setTextSize(textSize);
      	canvas.rotate(rotate);
        canvas.save();
        float textWidth = paint.measureText(markStr);
        int index = 0;
        int sheight = 100;
        float swidth = textWidth * 2 + 20;
        for (int positionY = sheight; positionY <= height; positionY += sheight) {
            float fromX = -width + (index++ % 2) * textWidth;
            for (float positionX = fromX; positionX < width; positionX += swidth) {
                canvas.drawText(markStr, positionX, positionY, paint);
            }
        }
        canvas.restore();
    }

    @Override
    public void setAlpha(int i) {

    }

    @Override
    public void setColorFilter(@Nullable ColorFilter colorFilter) {

    }

    @Override
    public int getOpacity() {
        return PixelFormat.UNKNOWN;
    }
}

一开始这方法生成的drawable都没有问题，也没有造成内存泄露。直到遇到了华为MT7 4.4系统，用这方法生成水印背景，导致所有设置该背景的Fragment内容全部变成倾斜。在前辈的帮助下，定位问题，可能是在draw()方法里面绘制背景的时候，用canvas.rotate(rotate);对整个画布进行旋转，华为MT7 4.4系统应该把所有的内容(包括listview等)都绘制在canvas上面，是得在进行选择的时候，不是对该背景的canvas进行旋转，而是旋转了所有的view。

更新：经过多个机型匹配发现，这是Android4.4手机系统都会有的问题

前辈说在onDraw()函数加canvas.save()和canvas.restore()可以解决问题，还没验证

对生成自定义drawable进行了改造。

public class WarterMarkDrawable extends Drawable {

    Context context;
    String markStr = "";
    int textColor = Color.BLACK;
    int textSize = 30;
    int backgroundColor = Color.WHITE;
    int rotate = -30;
    int alpha = 41;
    int density = 10;
    private Paint paint = new Paint();
    Bitmap bitmap = null;

    public WarterMarkDrawable(Context context, String watermark) {
        this.context = context;
        this.markStr = watermark;
        this.textColor = ContextCompat.getColor(context, R.color.water_mark_color);
        this.textSize = 42;
        this.backgroundColor = ContextCompat.getColor(context, R.color.background_6_0);
        this.rotate = -20;
        this.density = 7;
    }

    public WarterMarkDrawable(Context context, String watermark, Bitmap bitmap) {
        this.context = context;
        this.markStr = watermark;
        this.textColor = ContextCompat.getColor(context, R.color.water_mark_color);
        this.textSize = 42;
        this.backgroundColor = ContextCompat.getColor(context, R.color.background_6_0);
        this.rotate = -20;
        this.density = 7;
        this.bitmap = bitmap;
    }


    @Override
    public void draw(@NonNull Canvas canvas) {
        int width;
        int height;

        // 只有mt7才会进入该方法 在外面将水平drawable转换成bitmap后再旋转bitmap 绘制在canvas上
        if (bitmap != null) {
            Matrix matrix = new Matrix();
            // 根据中点旋转
            matrix.postRotate(rotate, bitmap.getWidth() / 2, bitmap.getHeight() / 2);
            canvas.drawBitmap(bitmap, matrix, paint);
        } else {
            // 华为MT7不能直接旋转画布 先生成一个水平的不旋转的drawable
            if (DeviceInfo.MODEL.getModel().contains("HUAWEI MT7")) {
                WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
                width = wm.getDefaultDisplay().getWidth() + 200;
                height = wm.getDefaultDisplay().getHeight() + 200;
            } else {
                // 普通系统走正常的生成水印代码
                width = getBounds().right + 200;
                height = getBounds().bottom + 200;
                canvas.rotate(rotate);
            }
            canvas.drawColor(backgroundColor);
            paint.setColor(textColor);
            paint.setAntiAlias(true);
            paint.setTextSize(textSize);
            canvas.save();
            float textWidth = paint.measureText(markStr);
            int index = 0;
            int sheight = 100;
            float swidth = textWidth * 2 + 20;
            for (int positionY = sheight; positionY <= height; positionY += sheight) {
                float fromX = -width + (index++ % 2) * textWidth;
                for (float positionX = fromX; positionX < width; positionX += swidth) {
                    canvas.drawText(markStr, positionX, positionY, paint);
                }
            }
            canvas.restore();
        }
    }

    @Override
    public void setAlpha(int i) {

    }

    @Override
    public void setColorFilter(@Nullable ColorFilter colorFilter) {

    }

    @Override
    public int getOpacity() {
        return PixelFormat.UNKNOWN;
    }
}

增加了一个bitmap成员，在华为MT7 系统上，先生成一个不旋转的水平的水印背景drawable，将改drawable转化成bitmap，然后对该bitmap进行旋转，绘制在canvas上，避免了旋转canvas。

在外围调用的时候

// 先生成一张drawable 若是华为MT7系统 则生成的是不旋转的水平drawable
WarterMarkDrawable waterDrawable = new WarterMarkDrawable(context, watermark);

// 华为MT7不能直接在画布上旋转
if (DeviceInfo.MODEL.getModel().contains("HUAWEI MT7")) {
 	WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
	// 将drawable转化成bitmap
 	int width = wm.getDefaultDisplay().getWidth() + 200;
	int height = wm.getDefaultDisplay().getHeight() + 200;
	Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
	Canvas canvas = new Canvas(bitmap);
	waterDrawable.draw(canvas);
  	// 再生成一次drawable，这次传入bitmap后，会将改bitamp选择并绘制在canvas上，而不是选择canvas
	WarterMarkDrawable bitmapDrawable = new WarterMarkDrawable(context, watermark, bitmap);
} 
// ... 将waterDrawable 或 bitmapDrawable设置成view的背景，即完成水印背景的绘制

总结：简直被华为系统坑爆了。。。