在API级别28中找不到Canvas变量 [英] Can not find Canvas variables in API Level 28

问题描述

在Android 28中找不到以下 Canvas 变量。

The following Canvas Variables are not found in Android 28.

canvas.saveLayer(0, 0, getWidth(), getHeight(), null,
                Canvas.MATRIX_SAVE_FLAG |
                        Canvas.CLIP_SAVE_FLAG |
                        Canvas.HAS_ALPHA_LAYER_SAVE_FLAG |
                        Canvas.FULL_COLOR_LAYER_SAVE_FLAG |
                        Canvas.CLIP_TO_LAYER_SAVE_FLAG);

推荐答案

这些标志已在API 28中删除。请参见< a href = https://developer.android.com/sdk/api_diff/28/changes/android.graphics.Canvas rel = noreferrer>此处：

Those flags have been removed in API 28. See here:

类android.graphics.Canvas

Class android.graphics.Canvas

已删除的方法
int save（int）

Removed Methods int save(int)

已删除的字段
int CLIP_SAVE_FLAG

int CLIP_TO_LAYER_SAVE_FLAG

int FULL_COLOR_LAYER_SAVE_FLAG

int HAS_ALPHA_LAYER_SAVE_FLAG
int b $ b

Removed Fields int CLIP_SAVE_FLAG
int CLIP_TO_LAYER_SAVE_FLAG
int FULL_COLOR_LAYER_SAVE_FLAG
int HAS_ALPHA_LAYER_SAVE_FLAG
int MATRIX_SAVE_FLAG

该方法已在API 26中弃用。请参见此处：

That method was deprecated in API 26. See here:

此方法在API级别26中已弃用。
请改用saveLayer（float，float，float，float，Paint）。

This method was deprecated in API level 26. Use saveLayer(float, float, float, float, Paint) instead.

改用什么

根据API 28的 Canvas 源代码，您使用的所有标志组合起来等于 ALL_SAVE_FLAG ：

According to the Canvas source code for API 28, the flags you use all combine to be equal to the value of ALL_SAVE_FLAG:

public  static  final  int ALL_SAVE_FLAG =  0x1F;
public  static  final  int MATRIX_SAVE_FLAG =  0x01;
public  static  final  int CLIP_SAVE_FLAG =  0x02;
public  static  final  int HAS_ALPHA_LAYER_SAVE_FLAG =  0x04;
public  static  final  int FULL_COLOR_LAYER_SAVE_FLAG =  0x08;
public  static  final  int CLIP_TO_LAYER_SAVE_FLAG =  0x10;

来自同一源代码 Canvas＃saveLayer（左，上，右，底，油漆）默认使用 ALL_SAVE_FLAG ：

/**  
 * Convenience for {@link #saveLayer(RectF, Paint)} that takes the four float coordinates of the  
 * bounds rectangle. */
public int saveLayer(float left, float top, float right, float bottom, @Nullable Paint paint) {  
    return saveLayer(left, top, right, bottom, paint, ALL_SAVE_FLAG);  
}

因此，看起来您的代码等效于以下代码，您可以将其用作替换代码：

So, it looks like your code is equivalent to the following code which you can use as a replacement:

canvas.saveLayer(0, 0, getWidth(), getHeight(), null);

此版本的 saveLayer（）仅在API 21+上可用。要支持较低的API级别，请使用

This version of saveLayer() is only available on API 21+. To support lower API levels, use

canvas.saveLayer(0, 0, getWidth(), getHeight(), null, Canvas.ALL_SAVE_FLAG);

其中 Canvas.ALL_SAVE_FLAG 与相同或以上的值。

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