该程序可以测试出个人手机设备的分辨率，属于哪种dpi级别，以便开发参考。
main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:orientation="vertical" ><TextView android:id="@+id/screenSize"android:layout_width="fill_parent"android:layout_height="wrap_content"android:text="@string/screenSize"/><EditText android:id="@+id/size"android:layout_width="fill_parent"android:layout_height="wrap_content"android:inputType="numberDecimal"/><Buttonandroid:id="@+id/submit"android:layout_width="fill_parent"android:layout_height="wrap_content" android:text="@string/submit"/><EditText android:id="@+id/showWidth"android:layout_width="fill_parent"android:layout_height="wrap_content"android:inputType="text"android:editable="false"/><EditTextandroid:id="@+id/showDPI"android:layout_width="fill_parent"android:layout_height="wrap_content"android:inputType="text"android:editable="false"/></LinearLayout>string.xml
<?xml version="1.0" encoding="utf-8"?>
<resources><string name="hello">Hello World, AndroidDPI!</string><string name="app_name">AndroidDPI</string><string name="screenSize">输入该设备的屏幕大小：</string><string name="submit">确认</string>
</resources>Java代码：
package com.shine.android;import android.app.Activity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;public class AndroidDPI extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);final EditText size = (EditText) findViewById(R.id.size);final EditText showWidth = (EditText) findViewById(R.id.showWidth);final EditText showDPI = (EditText) findViewById(R.id.showDPI);Button submit = (Button) findViewById(R.id.submit);submit.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {if(size.length() == 0){size.setText("请输入该屏幕的尺寸");}else {DisplayMetrics dm = new DisplayMetrics();getWindowManager().getDefaultDisplay().getMetrics(dm);int width = dm.widthPixels;int height =dm.heightPixels;float sizeInt = Float.parseFloat(size.getText().toString());showWidth.setText("手机屏幕分辨率为："+width+"*"+height);double dpi = Math.sqrt(height*height +width*width)/sizeInt;String dpiType = "";if(dpi >320){dpiType = "属于xhdpi";}else if(dpi>240){dpiType = "属于hdpi";}else if(dpi>160){dpiType = "属于mdpi";}else if(dpi>120){dpiType = "属于ldpi";}showDPI.setText("手机DPI是:"+ dpi+ ","+ dpiType);}}});}
}
