Android数据存储方案(文件存储)

• 文件存储

文件存储

所有的文件会默认存储在/data/data/<packagename>/files/目录下

openFileOutput('data',Context.MODE_PRIVATE) //该方法返回一个FileOutputStream

举例

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

   <EditText
       android:id="@+id/edit_text"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"/>
   <TextView
       android:id="@+id/text_view"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"/>
   <Button
       android:text="存储"
       android:id="@+id/button"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"/>

</LinearLayout>

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button = findViewById(R.id.button);
        final EditText editText = findViewById(R.id.edit_text);
        final TextView textView = findViewById(R.id.text_view);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(editText.getText() != null){
                    save("data",editText.getText().toString()); //将文件存储
                    textView.setText(load("data"));  //取出文件
                }
            }
        });
    }
    //文件存储
    public void save(String fileName,String data){
        FileOutputStream out = null;
        BufferedWriter writer = null;
        try{
            out = openFileOutput(fileName, Context.MODE_PRIVATE);
            writer = new BufferedWriter((new OutputStreamWriter(out)));  //包装
            writer.write(data);   //写入文件
        }catch (IOException e){
            e.printStackTrace();
        }finally {
            try {
                if (writer != null) {
                    writer.close();
                }
            }catch (IOException e){
                e.printStackTrace();
            }
        }
    }

   //文件读取
    public String load(String fileName){
        FileInputStream in = null;
        BufferedReader reader = null;
        StringBuffer content = new StringBuffer();
        try{
            in = openFileInput(fileName);
            reader = new BufferedReader(new InputStreamReader(in));
            String line = "";
            while((line = reader.readLine()) != null){
                content.append(line);
            }
        }catch (IOException e){
            e.printStackTrace();
        }finally {
            if(reader != null){
                try{
                    reader.close();
                }catch (IOException e){
                    e.printStackTrace();
                }
            }
        }
        return content.toString();
    }

}

测试

image.png