android屏幕适配方案

根据UI提供标注图的标注尺寸，设置baseW（基准宽度）和baseH（基准高度）

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintWriter;


public class GenerateValueFiles {

    private static int baseW = 360;//基准宽度
    private static int baseH = 800;//基准高度

    private String dirStr = "./res";

    private final static String WTemplate = "<dimen name=\"x{0}\">{1}px</dimen>\n";
    private final static String HTemplate = "<dimen name=\"y{0}\">{1}px</dimen>\n";

    private final static String VALUE_TEMPLATE = "values-{0}x{1}";

    private static final String SUPPORT_DIMESION = "320,480;"
            + "480,800;480,854;"
            + "540,854;540,960;"
            + "600,800;600,1024;"
            + "640,960;"
            + "720,1184;720,1196;720,1208;720,1280;"
            + "768,1024;768,1280;"
            + "800,1280;"
            + "1080,1700;1080,1776;1080,1794;1080,1800;1080,1812;1080,1920;"
            + "1440,2416;1440,2560;"
            + "1600,2560;";

    private String supportStr = SUPPORT_DIMESION;

    public GenerateValueFiles(String supportStr) {
        this.supportStr += validateInput(supportStr);

        System.out.println(supportStr);

        File dir = new File(dirStr);
        if (!dir.exists()) {
            dir.mkdir();
        }
        System.out.println(dir.getAbsoluteFile());
    }

    /**
     * @param supportStr
     *            w,h_...w,h;
     * @return
     */
    private String validateInput(String supportStr) {
        StringBuffer sb = new StringBuffer();
        String[] vals = supportStr.split("_");
        int w = -1;
        int h = -1;
        String[] wh;
        for (String val : vals) {
            try {
                if (val == null || val.trim().length() == 0)
                    continue;

                wh = val.split(",");
                w = Integer.parseInt(wh[0]);
                h = Integer.parseInt(wh[1]);
            } catch (Exception e) {
                System.out.println("skip invalidate params : w,h = " + val);
                continue;
            }
            sb.append(w + "," + h + ";");
        }

        return sb.toString();
    }

    public void generate() {
        String[] vals = supportStr.split(";");
        for (String val : vals) {
            String[] wh = val.split(",");
            generateXmlFile(Integer.parseInt(wh[0]), Integer.parseInt(wh[1]));
        }
        generateDefaultXmlFile(baseW,baseH);
    }

    private void generateXmlFile(int w, int h) {

        StringBuffer sbForWidth = new StringBuffer();
        sbForWidth.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
        sbForWidth.append("<resources>");
        float cellw = w * 1.0f / baseW;

        System.out.println("width : " + w + "," + baseW + "," + cellw);
        for (int i = 1; i <=baseW; i++) {
            sbForWidth.append(WTemplate.replace("{0}", i + "").replace("{1}",
                    change(cellw * i) + ""));
        }
        sbForWidth.append("</resources>");

        StringBuffer sbForHeight = new StringBuffer();
        sbForHeight.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
        sbForHeight.append("<resources>");
        float cellh = w *1.0f/ baseW;
        System.out.println("height : "+ h + "," + baseH + "," + cellh);
        for (int i = 1; i <= baseH; i++) {
            sbForHeight.append(HTemplate.replace("{0}", i + "").replace("{1}",
                    change(cellh * i) + ""));
        }
        sbForHeight.append("</resources>");

        File fileDir = new File(dirStr + File.separator
                + VALUE_TEMPLATE.replace("{0}", h + "")//
                        .replace("{1}", w + ""));
        fileDir.mkdir();

        File layxFile = new File(fileDir.getAbsolutePath(), "lay_x.xml");
        File layyFile = new File(fileDir.getAbsolutePath(), "lay_y.xml");
        try {
            PrintWriter pw = new PrintWriter(new FileOutputStream(layxFile));
            pw.print(sbForWidth.toString());
            pw.close();
            pw = new PrintWriter(new FileOutputStream(layyFile));
            pw.print(sbForHeight.toString());
            pw.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    private void generateDefaultXmlFile(int w, int h){
        
         StringBuffer sbForWidth = new StringBuffer();
         sbForWidth.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
         sbForWidth.append("<resources>");
         float cellw = w * 1.0f / baseW;

         System.out.println("width : " + w + "," + baseW + "," + cellw);
         for (int i = 1; i < baseW; i++) {
             sbForWidth.append(WTemplate.replace("{0}", i + "").replace("{1}",
                     change(cellw * i) + "").replace("px", "dp"));
         }
         sbForWidth.append(WTemplate.replace("{0}", baseW + "").replace("{1}",
                 w + "").replace("px", "dp"));
         sbForWidth.append("</resources>");

         StringBuffer sbForHeight = new StringBuffer();
         sbForHeight.append("<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
         sbForHeight.append("<resources>");
         float cellh = h *1.0f/ baseH;
         System.out.println("height : "+ h + "," + baseH + "," + cellh);
         for (int i = 1; i < baseH; i++) {
             sbForHeight.append(HTemplate.replace("{0}", i + "").replace("{1}",
                     change(cellh * i) + "").replace("px", "dp"));
         }
         sbForHeight.append(HTemplate.replace("{0}", baseH + "").replace("{1}",
                 h + "").replace("px", "dp"));
         sbForHeight.append("</resources>");

         File fileDir = new File(dirStr + File.separator
                 + VALUE_TEMPLATE.substring(0, 6));
         fileDir.mkdir();

         File layxFile = new File(fileDir.getAbsolutePath(), "lay_x.xml");
         File layyFile = new File(fileDir.getAbsolutePath(), "lay_y.xml");
         try {
             PrintWriter pw = new PrintWriter(new FileOutputStream(layxFile));
             pw.print(sbForWidth.toString());
             pw.close();
             pw = new PrintWriter(new FileOutputStream(layyFile));
             pw.print(sbForHeight.toString());
             pw.close();
         } catch (FileNotFoundException e) {
             e.printStackTrace();
         }
    }
    public static float change(float a) {
        int temp = (int) (a * 100);
        return temp / 100f;
    }

    public static void main(String[] args) {
        String addition = "";
        try {
            if (args.length >= 3) {
                baseW = Integer.parseInt(args[0]);
                baseH = Integer.parseInt(args[1]);
                addition = args[2];
            } else if (args.length >= 2) {
                baseW = Integer.parseInt(args[0]);
                baseH = Integer.parseInt(args[1]);
            } else if (args.length >= 1) {
                addition = args[0];
            }
        } catch (NumberFormatException e) {

            System.err
                    .println("right input params : java -jar xxx.jar width height w,h_w,h_..._w,h;");
            e.printStackTrace();
            System.exit(-1);
        }

        new GenerateValueFiles(addition).generate();
    }

}

运行以上代码，会得到 res/values-x-x 文件，直接复制到项目的res路径下即可。

如何使用？

xml中指定width和height时，直接使用UI标注图中的尺寸，如UI标注128（不区分是宽度或高度，它们等效的），xml中就可以使用lay_x128。
lay_y和lay_x是一样的内容，不需要的可以删除所有的lay_x文件，唯一区别是lay_y的范围可以自由设置（比如800），在UI中如果有一个控件的UI标注尺寸为400，在lay_x中并没有lay_x400，这时你就可以使用lay_y400了。

有虚拟导航条的手机屏幕适配问题？

比如一款手机屏幕的物理尺寸为1920*1080，如果没有虚拟导航条它适配了values-1920x1080，但是有虚拟导航条时，它所适配的values文件就不是values-1920x1080了，而是高度减去虚拟导航条的values文件，比如虚拟导航条的高度为108，这时它适配的就是values-1812x1080。需要注意的是，虚拟导航条可以手动设置为隐藏，当隐藏状态下时，它适配的就是values-1920x1080了。
那么我们怎么知道虚拟导航条的高度？
可以写一个测试demo运行在这款手机上，执行如下代码：

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.Display;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        DisplayMetrics dm = new DisplayMetrics();
        Display display = getWindowManager().getDefaultDisplay();
        display.getMetrics(dm);
        TextView mTextView = (TextView) findViewById(R.id.main_tv);
        mTextView.setText("width:"+dm.widthPixels+",height:"+dm.heightPixels);
    }
}

运行该app就可以在textview中显示当前状态下适配屏幕所需要的宽和高了。

如果SUPPORT_DIMESION 中没有你想要适配屏幕的尺寸，你可以自行添加进去（格式为 宽，高）。