图片适配自定义控件

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一,实现效果(注意图片本身的格式会有很大的影响)

当宽度match_parent,设置宽高的比例值,确定高度值

当高度match_parent,设置宽高的比例值,确定宽度.

写二个自定义属性,ration比值,相对于谁?

    <declare-styleable name="RatioLayout">        <attr name="mRatio" format="float"></attr>        <attr name="mRelative" format="enum">            <enum name="width" value="0"></enum>            <enum name="height" value="1"></enum>        </attr>    </declare-styleable>

二.代码实现

<pre name="code" class="java">/** * 支持宽高自适应的组件，把需要适配的view作为它的孩子即可 */public class RatioLayout extends FrameLayout {    private float mRatio = 2.426f;//默认2.42    public static final int RELATIVE_WIDHT = 0;    public static final int RELATIVE_HEIGHT = 1;    private int mRelative = RELATIVE_WIDHT;//默认宽度match    public void setRatio(float ratio) {        mRatio = ratio;    }    public void setRelative(int relative) {        mRelative = relative;    }    public RatioLayout(Context context) {        this(context,null);    }    public RatioLayout(Context context, AttributeSet attrs) {        super(context, attrs);        //从xml中获取自定义属性        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.RatioLayout);        mRatio = typedArray.getFloat(R.styleable.RatioLayout_mRatio,mRatio);        mRelative = typedArray.getInt(R.styleable.RatioLayout_mRelative,RELATIVE_WIDHT);        typedArray.recycle();    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        //1.获取信息        int width = MeasureSpec.getSize(widthMeasureSpec);        int widthMode = MeasureSpec.getMode(widthMeasureSpec);        int height = MeasureSpec.getSize(heightMeasureSpec);        int heightMode = MeasureSpec.getMode(heightMeasureSpec);        //模式对应关系，matchparent/60dp ---- EXACTLY; wrapcontent-----> MeasureSpec.AT_MOST        if(widthMode == MeasureSpec.EXACTLY && mRelative == RELATIVE_WIDHT){            //情形一：宽度填充父窗体，高度自适应            //TODO:计算height,按照2.426的比例计算            int totalHeight = (int) (width / mRatio);            //2.测量孩子imageview            int childWidth = width - getPaddingLeft() - getPaddingRight(); //让自定义view支持padding功能            int childHeight = totalHeight - getPaddingTop() - getPaddingBottom();            int childWidthSpec = MeasureSpec.makeMeasureSpec(childWidth,MeasureSpec.EXACTLY);            int childHeightSpec = MeasureSpec.makeMeasureSpec(childHeight, MeasureSpec.EXACTLY);            measureChildren(childWidthSpec, childHeightSpec);            //3.决定自己的宽高            setMeasuredDimension(width, totalHeight);        }else if(heightMode == MeasureSpec.EXACTLY  && mRelative == RELATIVE_HEIGHT){            //情形二：高度固定，宽度自适应            int totalWidth = (int) (height * mRatio);            //2.测量孩子imageview            int childWidth = totalWidth - getPaddingLeft() - getPaddingRight(); //让自定义view支持padding功能            int childHeight = height - getPaddingTop() - getPaddingBottom();            int childWidthSpec = MeasureSpec.makeMeasureSpec(childWidth,MeasureSpec.EXACTLY);            int childHeightSpec = MeasureSpec.makeMeasureSpec(childHeight, MeasureSpec.EXACTLY);            measureChildren(childWidthSpec, childHeightSpec);            //3.决定自己的宽高            setMeasuredDimension(totalWidth, height);        }else {            super.onMeasure(widthMeasureSpec, heightMeasureSpec);            measureChildren(widthMeasureSpec,heightMeasureSpec);        }    }}

三总布局

<pre name="code" class="java"> <com.example.administrator.textdemo.RatioLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        app:mRelative="height"        app:mRatio="5"        >        <ImageView            android:src="@drawable/a"            android:layout_width="match_parent"            android:layout_height="match_parent"/>    </com.example.administrator.textdemo.RatioLayout>

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