自定义View尺寸进行适配

一、为什么要适配

因为Android市场的碎片化，导致APP界面再不同屏幕上显示的尺寸不一致。适配可以让布局，资源，用户流程匹配不同的屏幕。

二、布局的适配

1.不要写尺寸
2.LinearLayout的权重
3.RelativeLayout的布局方式
4.ContraintLayout
5.Percent-Layout来进行布局

三、图片资源适配

1.使用.9的图片

2.使用SVG实现缩放

3.使用多种尺寸的mipmap资源

四、用户流程适配

1.手机和平板不同的流程

五、限定符的适配

1.分辨率限定符 drawable-hdpi drawable-xdpi
2.尺寸限定符layout-small,layout-large
3.最小宽度的限定符values-sw ...
屏幕方向的限定符layout-land,layout-port

六、刘海屏的适配

根据各个厂商的官方文档适配

七、自定义View的适配

根据设计稿获取到缩放比例,在 View Measure的时候更改View的尺寸

缩放比例 = 使用设备尺寸 / 设计尺寸

获取缩放尺寸的工具类

import android.content.Context;
import android.util.DisplayMetrics;
import android.view.WindowManager;

import java.lang.reflect.Field;

public class UIUtils {
    //    工具类
    private static UIUtils instance;
    //    参考设备的宽和高 用来计算缩放比例
    public static final float STANDARD_WIDTH = 1080f;
    public static final float STANDARD_HEIGHT = 1920f;

    //实际设备信息  赋值    他是不知道横竖  1080  1920
    public static float displayMetricsWidth;
    public static float displayMetricsHeight;
    // 状态栏的宽高
    public static float systemBarHeight;

    //    applicaiton
    public static UIUtils getInstance(Context context) {
        if (instance == null) {
            instance = new UIUtils(context);
        }
        return instance;
    }

    public static UIUtils notityInstance(Context context) {
        instance = new UIUtils(context);
        return instance;
    }

    //    activity
    public static UIUtils getInstance() {
        if (instance == null) {
            throw new RuntimeException("UiUtil应该先调用含有构造方法进行初始化");
        }
        return instance;
    }

    private UIUtils(Context context) {
        // 获取设备的宽高
        WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        DisplayMetrics displayMetrics = new DisplayMetrics();
        // 获取到屏幕的宽高
        if (displayMetricsWidth == 0.0f || displayMetricsHeight == 0.0f) {
            //在这里得到设备的真实值
            windowManager.getDefaultDisplay().getMetrics(displayMetrics);
            systemBarHeight = getSystemBarHeight(context);
            //横屏
            if (displayMetrics.widthPixels > displayMetrics.heightPixels) {
                this.displayMetricsWidth = (float) (displayMetrics.heightPixels);
                this.displayMetricsHeight = (float) (displayMetrics.widthPixels - systemBarHeight);
            } else {
                //                竖屏
                this.displayMetricsWidth = (float) (displayMetrics.widthPixels);
                this.displayMetricsHeight = (float) (displayMetrics.heightPixels - systemBarHeight);
            }
            //            状态栏
        }
    }

    //
    public float getHorizontalScaleValue() {
        return ((float) (displayMetricsWidth)) / STANDARD_WIDTH;
    }

    public float getVerticalScaleValue() {
        return ((float) (displayMetricsHeight)) / (STANDARD_HEIGHT - systemBarHeight);
    }

    private int getSystemBarHeight(Context context) {
        return getValue(context, "com.android.internal.R$dimen", "system_bar_height", 48);
    }

    public int getWidth(int width) {
        return Math.round((float) width * this.displayMetricsWidth / STANDARD_WIDTH);
    }

    public int getHeight(int height) {
        return Math.round((float) height * this.displayMetricsHeight / (STANDARD_HEIGHT - systemBarHeight));
    }

    private int getValue(Context context, String dimeClass, String system_bar_height, int defaultValue) {
        //        com.android.internal.R$dimen    system_bar_height   状态栏的高度
        try {
            Class<?> clz = Class.forName(dimeClass);
            Object object = clz.newInstance();
            Field field = clz.getField(system_bar_height);
            int id = Integer.parseInt(field.get(object).toString());
            return context.getResources().getDimensionPixelSize(id);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return defaultValue;
    }

}

重写容器View,让容器View中的控件都被缩放

 @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (flag) {
            flag = false;
            // 获取水平和数值方向的缩放比例
            float scaleX = UIUtils.getInstance(getContext()).getHorizontalScaleValue();
            float scaleY = UIUtils.getInstance(getContext()).getVerticalScaleValue();
            int childCount = this.getChildCount();
            // 缩放所有子控件
            for (int i = 0; i < childCount; i++) {
                View child = this.getChildAt(i);
                LayoutParams layoutParams = (LayoutParams) child.getLayoutParams();
                layoutParams.width = (int) (layoutParams.width * scaleX);
                layoutParams.height = (int) (layoutParams.height * scaleY);
                layoutParams.leftMargin = (int) (layoutParams.leftMargin * scaleX);
                layoutParams.rightMargin = (int) (layoutParams.rightMargin * scaleX);
                layoutParams.topMargin = (int) (layoutParams.topMargin * scaleY);
                layoutParams.bottomMargin = (int) (layoutParams.bottomMargin * scaleY);
            }
        }
    }