權限的開放,在AndroidManifest.xml加入
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
權限的開放,在AndroidManifest.xml加入
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
MainActivity.java
package tw.idv.charleslin74.sdcardreadwritetest; import android.os.Bundle; import android.os.Environment; import android.support.v7.app.AppCompatActivity; import android.widget.TextView; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); TextView showerror = (TextView) findViewById(R.id.showerror); String aaa = Environment.<em>getExternalStorageDirectory</em>().getPath(); showerror.setText(aaa); } }
activity_main.xml
寫入資料
FileOutputStream fout = openFileOutput("myfile.txt",MODE_PRIVATE); BufferedOutputStream buffout = new BufferedOutputStream(fout); buffout.write("這是測試".getBytes()); buffout.close();
讀取資料
寫入資料
SharedPreferences spToDo = getSharedPreferences("prefile",MODE_PRIVATE); spToDo.edit().putString("username","superman").commit();
放進資料的方式有putBoolean,putFloat,putInt,putLong,putString,依需求自已改變.
package com.example.charleslin.keybackalarm;
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.charleslin.playlivevideo" > <uses-permission android:name="android.permission.INTERNET" > </uses-permission> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name=".MainActivity" android:label="@string/app_name" android:configChanges="orientation|screenSize" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".VideoViewActivity" android:configChanges="orientation|screenSize" > </activity> </application> </manifest>
MainActivity.java
如果你的APP是一個靜態頁面的話,它想刷新就讓它刷新,但是如果你頁面的資料是來自網路上或者你正在看影片聽音樂,轉個螢幕就重新看重新聽,你不被使用者打死才怪.
那為什麼轉個螢幕就必須重新開始呢??