安卓开发之获取SD卡空间数据

 package com.lidaochen.getsdcardspace;
 
 import android.os.Environment;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.widget.EditText;
 import android.widget.TextView;
 
 import java.io.File;
 import java.util.Formatter;
 
 public class MainActivity extends AppCompatActivity {
     private TextView et_total;
     private TextView et_useAble;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         // 1.找到两个EditText控件
         et_total = (TextView)findViewById(R.id.et_total);
         et_useAble = (TextView)findViewById(R.id.et_useAble);
         // 2.获取SD卡总大小和可用空间
         File file = Environment.getExternalStorageDirectory();
         long totalSpace = file.getTotalSpace(); // 总大小
         long useAbleSpace = file.getUsableSpace(); // 可用空间大小
         // 3.展示到TextView上
         et_total.setText("总大小：" + String.format("%.2f", (double)totalSpace / (1024 * 1024 * 1024)) + "GB");
         et_useAble.setText("可用空间：" + String.format("%.2f", (double)useAbleSpace / (1024 * 1024 * 1024)) + "GB");
     }
 }