DataCleanUtil.java

import android.content.Context;
import android.os.Environment;

import java.io.File;
import java.math.BigDecimal;

/**
 * @description :快取工具類
 */
public class DataCleanUtil {

    /**
     * 獲取快取大小
     * @param context
     * @return
     * @throws Exception
     */
    public static String getTotalCacheSize(Context context) throws Exception {
        long cacheSize = getFolderSize(context.getCacheDir());
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            cacheSize += getFolderSize(context.getExternalCacheDir());
        }
        return getFormatSize(cacheSize);
    }


    /**
     * 清除所有快取
     * @param context
     */
    public static void clearAllCache(Context context) {
        deleteDir(context.getCacheDir());
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            deleteDir(context.getExternalCacheDir());
        }
    }

    /**
     * 刪除檔案目錄
     * @param dir
     * @return
     */
    private static boolean deleteDir(File dir) {
        if (dir != null && dir.isDirectory()) {
            String[] children = dir.list();
            for (int i = 0; i < children.length; i++) {
                boolean success = deleteDir(new File(dir, children[i]));
                if (!success) {
                    return false;
                }
            }
        }
        return dir.delete();
    }

    /**
     * MethodsTitle: 獲取檔案
     * 步驟：
     * Context.getExternalFilesDir() --> SDCard/Android/data/你的應用的包名/files/目錄，一般放一些長時間儲存的資料
     * Context.getExternalCacheDir() --> SDCard/Android/data/你的應用包名/cache/目錄，一般存放臨時快取資料
     * @param file
     * @return
     * @throws Exception
     */
    public static long getFolderSize(File file) throws Exception {
        long size = 0;
        try {
            File[] fileList = file.listFiles();
            for (int i = 0; i < fileList.length; i++) {
                // 如果下面還有檔案
                if (fileList[i].isDirectory()) {
                    size = size + getFolderSize(fileList[i]);
                } else {
                    size = size + fileList[i].length();
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return size;
    }

    /**
     * 格式化單位並計算快取的大小
     * @param size
     * @return
     */
    public static String getFormatSize(double size) {
        double kiloByte = size / 1024;
        if (kiloByte < 1) {
            //            return size + "Byte";
            return "0K";
        }

        double megaByte = kiloByte / 1024;
        if (megaByte < 1) {
            BigDecimal result1 = new BigDecimal(Double.toString(kiloByte));
            return result1.setScale(2, BigDecimal.ROUND_HALF_UP)
                    .toPlainString() + "KB";
        }

        double gigaByte = megaByte / 1024;
        if (gigaByte < 1) {
            BigDecimal result2 = new BigDecimal(Double.toString(megaByte));
            return result2.setScale(2, BigDecimal.ROUND_HALF_UP)
                    .toPlainString() + "MB";
        }

        double teraBytes = gigaByte / 1024;
        if (teraBytes < 1) {
            BigDecimal result3 = new BigDecimal(Double.toString(gigaByte));
            return result3.setScale(2, BigDecimal.ROUND_HALF_UP)
                    .toPlainString() + "GB";
        }

        BigDecimal result4 = new BigDecimal(teraBytes);
        return result4.setScale(2, BigDecimal.ROUND_HALF_UP)
                .toPlainString() + "TB";
    }
}
 

程式碼中使用(MainActivity.java)：

import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private TextView cache_size;

    private Button clear;

    String cacheSize;

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

        cache_size = (TextView) findViewById(R.id.cache_size);
        clear = (Button) findViewById(R.id.clear);

        getTotalCacheSize();

        clear.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                clearCache();
            }
        });
    }

    private void clearCache() {
        new AlertDialog.Builder(MainActivity.this)
                .setTitle("是否清楚快取?")
                .setMessage("確認清除所有的快取")
                .setPositiveButton("清除", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        if (cacheSize.equals("0K")) {
                            Toast.makeText(MainActivity.this, "沒有快取可以清除", Toast.LENGTH_SHORT).show();
                            return;
                        }
                        //在子執行緒執行刪除快取
                        new Thread(new Runnable() {
                            @Override
                            public void run() {
                                DataCleanUtil.clearAllCache(MainActivity.this);
                                //在主執行緒執行更新UI操作
                                runOnUiThread(new Runnable() {
                                    @Override
                                    public void run() {
                                        Toast.makeText(MainActivity.this, "清除快取成功", Toast.LENGTH_SHORT).show();
                                        getTotalCacheSize();
                                    }
                                });
                            }
                        }).start();
                    }
                })
                .setNegativeButton("取消", null).show();
    }

    private void getTotalCacheSize() {
        try {
            //這個操作要放在try-catch當中
            cacheSize = DataCleanUtil.getTotalCacheSize(MainActivity.this);
            cache_size.setText(cacheSize);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
 

activity_main.xml

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/cache_size"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="5dp"
        android:layout_centerInParent="true"
        android:textSize="18sp"
        android:textColor="#f2fa" />

    <Button
        android:id="@+id/clear"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/cache_size"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="10dp"
        android:padding="5dp"
        android:text="清理記憶體"/>

</RelativeLayout>