可以设置最大宽高的FrameLayout

支持相对父控件的半分比设置

默认优先比例设置

不支持参数小于零

MaxLayout.java

import android.util.DisplayMetrics;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.view.WindowManager;/*** Created by wangxingsheng on 2018/6/8.** 可以设置最大宽高的FrameLayout* 默认优先比例设置* 不支持参数小于零**/
public class MaxLayout extends FrameLayout {private float mMaxHeightRatio = -1f;// 优先级高private float mMaxHeight = -1f;// 优先级低private float mMaxWidthRatio = -1f;// 优先级高private float mMaxWidth = -1f;// 优先级低private int parentWidth;private int parentHeight;private boolean firstHeightRatio = true;//高默认优先比例设置private boolean firstWidthRatio = true;//宽默认优先比例设置public MaxLayout(Context context) {super(context);}public MaxLayout(Context context, AttributeSet attrs) {super(context, attrs);initAttrs(context, attrs);}public MaxLayout(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);initAttrs(context, attrs);}private void initAttrs(Context context, AttributeSet attrs) {TypedArray a = context.obtainStyledAttributes(attrs,R.styleable.MaxLayout);if(a!=null){firstHeightRatio = a.getBoolean(R.styleable.MaxLayout_first_ratio_height,true);firstWidthRatio = a.getBoolean(R.styleable.MaxLayout_first_ratio_width,true);mMaxHeightRatio = a.getFloat(R.styleable.MaxLayout_max_height_ratio, -1f);mMaxHeight = a.getDimension(R.styleable.MaxLayout_max_height, -1f);mMaxWidthRatio = a.getFloat(R.styleable.MaxLayout_max_width_ratio, -1f);mMaxWidth = a.getDimension(R.styleable.MaxLayout_max_width, -1f);a.recycle();}}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {initParentWH();initWH();int heightMode = MeasureSpec.getMode(heightMeasureSpec);int heightSize = MeasureSpec.getSize(heightMeasureSpec);int maxHeightMeasureSpec = MeasureSpec.makeMeasureSpec(heightSize <= mMaxHeight ? heightSize : (int) mMaxHeight, heightMode);int widthMode = MeasureSpec.getMode(widthMeasureSpec);int widthSize = MeasureSpec.getSize(widthMeasureSpec);int maxWidthMeasureSpec = MeasureSpec.makeMeasureSpec(widthSize <= mMaxWidth ? widthSize : (int) mMaxWidth, widthMode);super.onMeasure(maxWidthMeasureSpec, maxHeightMeasureSpec);}/*** 计算需要设置的宽高*/private void initWH() {if((firstHeightRatio && mMaxHeightRatio > 0)|| (!firstHeightRatio && mMaxHeight < 0)){mMaxHeight = mMaxHeightRatio * parentHeight;}if((firstWidthRatio && mMaxWidthRatio > 0)|| (!firstWidthRatio && mMaxWidth < 0)){mMaxWidth = mMaxWidthRatio * parentWidth;}}/*** 获取父控件的宽高*/private void initParentWH() {ViewGroup parent = (ViewGroup) getParent();if(null != parent){parentWidth = parent.getWidth();parentHeight = parent.getHeight();}else {WindowManager wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);DisplayMetrics dm = new DisplayMetrics();if (wm != null) {wm.getDefaultDisplay().getMetrics(dm);parentWidth = dm.widthPixels;parentHeight = dm.heightPixels;}}}
}

attrs.xml

    <declare-styleable name="MaxLayout"><attr name="max_height_ratio" format="float"/><attr name="max_height" format="dimension"/><attr name="max_width_ratio" format="float"/><attr name="max_width" format="dimension"/><attr name="first_ratio_height" format="boolean"/><attr name="first_ratio_width" format="boolean"/></declare-styleable>