android内存优化-背景渲染

背景：在android中使用大的背景图（ImageView）非常占用内存。如果背景图是激变或纯色，则直接设置颜色替代图片则非常有必要。一方面显示效果更有保证；二是内存会省下来不少呢~

方法一：布局设置背景图

1.添加布局文件

loading_bg.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:type="linear"
        android:startColor = "#105AA9"
        android:endColor = "#1B9FC5"
        android:angle="270"/>
    <corners
        android:radius="0dip"/>

</shape>

2.引用

android:background="@drawable/loading_bg"

方法二：代码设置

1.创建view类

public class MyView extends View {

    public MyView(Context context) {
        super(context);
    }

    public MyView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //获取View的宽高
        int width = getWidth();
        int height = getHeight();

        int colorStart = getResources().getColor(R.color.begin);
        int color1 = Color.GRAY;
        int colorEnd = getResources().getColor(R.color.end);

        Paint paint = new Paint();
        LinearGradient backGradient = new LinearGradient(0, 0, 0, height, new int[]{colorStart ,colorEnd}, null, Shader.TileMode.CLAMP);
        paint.setShader(backGradient);
        canvas.drawRect(0, 0, width, height, paint);
    }
}

2.引用

<cn.xx.xx.MyView
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

android内存优化-背景渲染

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