android dimens density適配檔案生成-有解無憂

在撰寫xml的時候，我們直接指定一個固定一個控制元件的寬高，給一個固定的dp值，在不同的螢屏上顯示差別很大，導致有的手機布局無法正常顯示，所以需要適配螢屏

古老的適配一般就是自己計算，然后生成檔案，以前自己也這么干過，直接規定好自己需要的尺寸，然后代碼去計算生成，然后復制到專案中使用，一般常用的尺寸如下

執行代碼會根據定義的尺寸生成出對應的 dimens.xml 類，下面是代碼

package com.example.myapplication;

import android.util.Log;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigDecimal;

public class MakeUtils {

    private static final String XML_HEADER = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\r\n";
    private static final String XML_RESOURCE_START = "<resources>\r\n";
    private static final String XML_RESOURCE_END = "</resources>\r\n";
    private static final String XML_DIMEN_TEMPLETE = "<dimen name=\"qb_%1$spx_%2$d\">%3$.2fdp</dimen>\r\n";

    private static final String XML_BASE_DPI = "<dimen name=\"base_dpi\">%ddp</dimen>\r\n";
    private  static final int MAX_SIZE = 720;

    private static final String XML_NAME = "dimens.xml";

    public static float px2dip(float pxValue, int sw,int designWidth) {
        float dpValue =   https://www.cnblogs.com/LiuZhen/archive/2021/02/03/(pxValue/(float)designWidth) * sw;
        BigDecimal bigDecimal = new BigDecimal(dpValue);
        float dp = bigDecimal.setScale(2, BigDecimal.ROUND_HALF_UP).floatValue();
        return dp;
    }

    /**
     * 生成所有的尺寸資料
     */
    private static String createDimens(DimenTypes type, int designWidth) {
        float dpValue;
        String temp;
        StringBuilder sb = new StringBuilder();
        try {
            sb.append(XML_HEADER);
            sb.append(XML_RESOURCE_START);
            //備份生成的相關資訊
            temp = String.format(XML_BASE_DPI, type.getSwWidthDp());
            sb.append(temp);
            for (int i = 0; i <= MAX_SIZE; i++) {

                dpValue = px2dip((float) i,type.getSwWidthDp(),designWidth);
                temp = String.format(XML_DIMEN_TEMPLETE,"", i, dpValue);
                sb.append(temp);
            }
            sb.append(XML_RESOURCE_END);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sb.toString();
    }

    /**
     * 生成的目標檔案夾
     */
    public static void create(int designWidth, DimenTypes type, String buildDir) {
        try {
            //生成規則
            final String folderName;
            if (type.getSwWidthDp() > 0) {
                //適配Android 3.2+
                folderName = "values-sw" + type.getSwWidthDp() + "dp";
            }else {
                return;
            }

            //生成目標目錄
            File file = new File(buildDir + File.separator + folderName);
            if (!file.exists()) {
                file.mkdirs();
            }
            Log.e("===",file.getAbsolutePath());
            //生成values檔案
            FileOutputStream fos = new FileOutputStream(file.getAbsolutePath() + File.separator + XML_NAME);
            fos.write(createDimens(type,designWidth).getBytes());
            fos.flush();
            fos.close();


        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

View Code

package com.example.myapplication;

/**
 * created by YooJin.
 * date: 2021/2/3 13:50
 * ldpi: 120 density:1dp=0.75px 代表尺寸 240*320
 * mdpi: 160 density:1dp=1px 代表尺寸 320*480
 * hdpi: 240 density:1dp=1.5px 代表尺寸 480*800
 * xhdpi: 320 density:1dp=2px 代表尺寸720*1280
 * xxhdpi: 480 density:1dp=3px 代表尺寸1080*1920
 */
enum DimenTypes {

    DP_sw__160(160),
    DP_sw__240(240),
    DP_sw__280(280),
    DP_sw__320(320),  
    DP_sw__360(360),
    DP_sw__400(400),
    DP_sw__420(420),
    DP_sw__440(440),
    DP_sw__480(480),
    DP_sw__560(560),
    DP_sw__640(640),
    DP_sw__720(720),
    DP_sw__800(800);

    /**
     * 螢屏最小寬度
     */
    private int swWidthDp;

    DimenTypes(int swWidthDp) {

        this.swWidthDp = swWidthDp;
    }

    public int getSwWidthDp() {
        return swWidthDp;
    }

    public void setSwWidthDp(int swWidthDp) {
        this.swWidthDp = swWidthDp;
    }

}

View Code

package com.example.myapplication;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Environment;
import android.widget.TextView;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    /**
     * 設計稿尺寸，從零開始，生成的最大尺寸
     */
    private static final int DESIGN_WIDTH = 375;

    String[] permissions = new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE};
    List<String> mPermissionList = new ArrayList<>();

    private static final int PERMISSION_REQUEST = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        checkPermission();
        String path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath() + File.separator + "res";
        TextView tvTag = findViewById(R.id.tv_tag);
        tvTag.setText(path);
        DimenTypes[] values = DimenTypes.values();
        for (DimenTypes value : values) {
            MakeUtils.create(DESIGN_WIDTH, value, path);
        }
    }

    private void checkPermission() {
        mPermissionList.clear();

        //判斷哪些權限未授予
        for (int i = 0; i < permissions.length; i++) {
            if (ContextCompat.checkSelfPermission(this, permissions[i]) != PackageManager.PERMISSION_GRANTED) {
                mPermissionList.add(permissions[i]);
            }
        }
        /**
         * 判斷是否為空
         */
        if (mPermissionList.isEmpty()) {//未授予的權限為空，表示都授予了

        } else {//請求權限方法
            String[] permissions = mPermissionList.toArray(new String[mPermissionList.size()]);//將List轉為陣列
            ActivityCompat.requestPermissions(MainActivity.this, permissions, PERMISSION_REQUEST);
        }
    }

    /**
     * 回應授權
     * 這里不管用戶是否拒絕，都進入首頁，不再重復申請權限
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case PERMISSION_REQUEST:

                break;
            default:
                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
                break;
        }
    }

}