.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout 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" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.hanqi.application3.DataActivity1" android:orientation="vertical"> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/et_1" android:hint="Key"/> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/et_2" android:hint="Value"/> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <Button android:layout_width="0dp" android:layout_height="wrap_content" android:text="保存" android:layout_weight="1" android:onClick="bt1_onClick"/> <Button android:layout_width="0dp" android:layout_height="wrap_content" android:text="读取" android:layout_weight="1" android:onClick="bt2_onClick"/> </LinearLayout> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/et_3" android:hint="要保存的内容"/> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:id="@+id/et_4" android:hint="从文件中读取的内容"/> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <Button android:layout_width="0dp" android:layout_height="wrap_content" android:text="保存" android:layout_weight="1" android:onClick="bt3_onClick"/> <Button android:layout_width="0dp" android:layout_height="wrap_content" android:text="读取" android:layout_weight="1" android:onClick="bt4_onClick"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content"> <Button android:layout_width="0dp" android:layout_height="wrap_content" android:text="保存文件" android:layout_weight="1" android:onClick="bt5_onClick"/> <Button android:layout_width="0dp" android:layout_height="wrap_content" android:text="读取文件" android:layout_weight="1" android:onClick="bt6_onClick"/> </LinearLayout> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/da1" android:id="@+id/iv_4"/> </LinearLayout>
.java
package com.hanqi.application3; import android.content.SharedPreferences; import android.content.res.AssetManager; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.EditText; import android.widget.ImageView; import android.widget.Toast; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.PrintStream; public class DataActivity1 extends AppCompatActivity { EditText et1; EditText et2; EditText et3; EditText et4; ImageView iv4; SharedPreferences sp; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_data1); et1=(EditText)findViewById(R.id.et_1); et2=(EditText)findViewById(R.id.et_2); et3=(EditText)findViewById(R.id.et_3); et4=(EditText)findViewById(R.id.et_4); iv4= (ImageView)findViewById(R.id.iv_4); //1.获取sp的实例，制定了文件名和操作模式 MODE_PRIVATE私有 sp = getSharedPreferences("mydata",MODE_PRIVATE); } //操作assets内的文件 public void bt5_onClick(View v) { //1.获取AssetManager AssetManager am = getAssets(); try{ //2.打开文件,获取输入流 InputStream is = am.open("denglu.jpg"); //3.获取输出流 FileOutputStream fos2 = openFileOutput("denglu2.jpg",MODE_PRIVATE); //4.边度编写 byte[] bb2 = new byte[1024]; int ii2 = 0; while ((ii2 = is.read(bb2))>0) { fos2.write(bb2,0,ii2); } fos2.close(); is.close(); Toast.makeText(DataActivity1.this, "保存成功", Toast.LENGTH_SHORT).show(); } catch (Exception e) { e.printStackTrace(); Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show(); } } //从手机内部存储读图片文件 public void bt6_onClick(View v) { //改变ImageView的图片来源，指向手机存储空间 //1.获取文件存储的绝对路径 String filepath = getFilesDir().getAbsolutePath(); //2.组合完整路径 filepath += "/denglu2.jpg"; //3.生成位图实例 Bitmap bm2 = BitmapFactory.decodeFile(filepath); //4.改变ImageView的图片来源 iv4.setImageBitmap(bm2); } //文件名 final String FILENAME = "test.txt"; public void bt3_onClick(View v) { //1.获取要存储的内容 String content = et3.getText().toString(); //2.获取输出流 try { FileOutputStream fos1 = openFileOutput(FILENAME, MODE_APPEND); //3.构造一个打印输出流 PrintStream pm1 = new PrintStream(fos1); //4.写入内容 pm1.println(content); pm1.close(); fos1.close(); Toast.makeText(DataActivity1.this, "保存成功", Toast.LENGTH_SHORT).show(); } catch (Exception e) { e.printStackTrace(); Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show(); } } public void bt4_onClick(View v) { try { //1.获取输入流 FileInputStream fis1 = openFileInput(FILENAME); //2.定义读取的数组 byte[] bt11 = new byte[1024]; //3.读出数据的长度 int ii = 0; StringBuilder bb1 = new StringBuilder (); while ((ii = fis1.read(bt11))>0) { bb1.append(new String(bt11,0, ii)); } fis1.close(); //设置显示读出的内容 et4.setText(bb1); Toast.makeText(DataActivity1.this, "显示成功", Toast.LENGTH_SHORT).show(); } catch (Exception e) { e.printStackTrace(); Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show(); } } //保存 public void bt1_onClick(View v) { //1.获取Key和Value String key = et1.getText().toString(); String value = et2.getText().toString(); if (key.length() ==0||value.length() == 0) { Toast.makeText(DataActivity1.this, "key或value不能为空", Toast.LENGTH_SHORT).show(); } else { //2.取得Editor edit编辑器 SharedPreferences.Editor editor = sp.edit(); //3.放入键值对 editor.putString(key,value); //4.提交保存 boolean b = editor.commit(); if (b) { Toast.makeText(DataActivity1.this, "保存成功", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(DataActivity1.this, "保存失败", Toast.LENGTH_SHORT).show(); } } } //读取 public void bt2_onClick(View v) { //1.获取要读的key String key = et1.getText().toString(); //2.读并设置文本框 et2.setText(sp.getString(key,"没有发现key")); } }