package com.example.lenovo.myapplication;import android.content.SharedPreferences;import android.content.res.AssetManager;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.os.Environment;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.EditText;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.InputStream;import java.io.PrintStream;public class MainActivity extends AppCompatActivity {    EditText et1;    TextView tv1;    ImageView iv1;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        et1 = (EditText) findViewById(R.id.et1);        tv1 = (TextView) findViewById(R.id.tv1);        iv1 = (ImageView) findViewById(R.id.iv1);    }    public void bt_1(View v) {        //1-得到SharedPreferences        SharedPreferences sharedPreferences = getSharedPreferences("abc", MODE_PRIVATE);        //2-得到编译器        SharedPreferences.Editor editor = sharedPreferences.edit();        //3-使用Editor添加数据        editor.putString("a", "abcdfe");        editor.putLong("b", 123456);        //4-提交保存        editor.commit();        Toast.makeText(MainActivity.this, "保存成功", Toast.LENGTH_SHORT).show();    }    //读取    public void bt_2(View v) {        SharedPreferences sharedPreferences = getSharedPreferences("abc", MODE_PRIVATE);        String s = sharedPreferences.getString("b", null);        Toast.makeText(MainActivity.this, "key=b" + "value=" + s, Toast.LENGTH_SHORT).show();    }    //写内部文件    public void bt_3(View v) {        //从内存里写入文件        try {            //1-得到内部的存储文件            File file = getFilesDir();            String path = file.getAbsolutePath();            Toast.makeText(MainActivity.this, "path=" + path, Toast.LENGTH_SHORT).show();            //2-用输出流写入文件            FileOutputStream fileOutputStream = openFileOutput("text.txt", MODE_PRIVATE);            //3-写入文件内容            PrintStream printStream = new PrintStream(fileOutputStream);            String str = et1.getText().toString();            printStream.println(str);            //printStream.println("自动换行");            printStream.close();            Toast.makeText(MainActivity.this, "保存成功", Toast.LENGTH_SHORT).show();        } catch (Exception ex) {            Toast.makeText(MainActivity.this, "保存失败", Toast.LENGTH_SHORT).show();        }    }    //    public void bt_4(View v) {        try {            //输入流            FileInputStream fis = openFileInput("text.txt");            //1-定义byte[]            byte[] b = new byte[1024];            int i = 0;//读到的数据长度            String str1 = "";            //2-循环读            while ((i = fis.read(b)) > 0) {                String str = new String(b, 0, i);                str1 += str;            }            fis.close();            tv1.setText(str1);        } catch (Exception ex) {        }    }    public void bt_5(View v) {        try {            //操作assets目录的文件            //1-得到assets目录管理器Manager            AssetManager assetManager = getAssets();            //2-操作资产目录，边读边写入            //1)-先读文件到内存 inputstream            InputStream inputStream = assetManager.open("abc.jpg");            //2)-写文件到目录outputstream            FileOutputStream fileOutputStream = openFileOutput("text.jpg", MODE_PRIVATE);            //先读后写入            byte[] b = new byte[1024];            int i = 0;            while ((i = inputStream.read(b)) > 0) {                fileOutputStream.write(b, 0, i);            }            fileOutputStream.close();            inputStream.close();            Toast.makeText(MainActivity.this, "保存文件成功", Toast.LENGTH_SHORT).show();        } catch (Exception e) {            Toast.makeText(MainActivity.this, "保存文件出错", Toast.LENGTH_SHORT).show();        }    }    public void bt_6(View v) {        //3-得到文件路径        String path = getFilesDir().getAbsolutePath() + "/text.jpg";        Toast.makeText(MainActivity.this, "path=" + path, Toast.LENGTH_SHORT).show();        //2-从内部存储的图片得到Bitmap  BitmapFactory.decodeFile("文件路径");        Bitmap bm = BitmapFactory.decodeFile(path);        //1-设置图片视图的图片数据来源        iv1.setImageBitmap(bm);    }    public void bt_7(View v) {        //1-判断SC卡是否挂载        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {            //得到文本框内容            String str = et1.getText().toString();            try {                //写入                //1-构造输出流                //1）得到文件路径。得到SD卡的根目录                //String path=Environment.getExternalStorageDirectory().getCanonicalPath();                //2)得到包名对应的目录                String path = getExternalFilesDir("Musics").getCanonicalPath();                Toast.makeText(MainActivity.this, "path=" + path, Toast.LENGTH_SHORT).show();                //2）构造                FileOutputStream fos = new FileOutputStream("path");                PrintStream printStream = new PrintStream(fos);                printStream.print(str);                printStream.close();                fos.close();                Toast.makeText(MainActivity.this, "存储成功", Toast.LENGTH_SHORT).show();            } catch (Exception e) {                Toast.makeText(MainActivity.this, "存储失败", Toast.LENGTH_SHORT).show();            }        } else {            Toast.makeText(MainActivity.this, "SD没有", Toast.LENGTH_SHORT).show();        }    }    public void bt_8(View v) {        //1-判断SC卡是否挂载        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))        {            try {                String path = getExternalFilesDir("Music").getCanonicalPath() + "/text.jpg";                FileInputStream fls=new FileInputStream(path);                byte[]b=new byte[1024];                int i=0;                String str="";                while ((i=fls.read(b))>0)                {                    str+=new String(b,0,i);                }                fls.close();                Toast.makeText(MainActivity.this, "读取成功，文件内容："+str, Toast.LENGTH_SHORT).show();            }            catch (Exception e)            {                Toast.makeText(MainActivity.this, "读取失败", Toast.LENGTH_SHORT).show();            }        }        else        {            Toast.makeText(MainActivity.this, "SD没有", Toast.LENGTH_SHORT).show();        }    }}

 

 

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