读取数据

读取数据

1.首先界面布局，做成简单的登陆界面就可以
2.实现功能
界面代码：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    tools:context="com.example.administrator.denglujiemian.MainActivity">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="用户名："
            android:textSize="60px"
            android:textColor="#FF0000" />
        <EditText
            android:id="@+id/editText1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:minWidth="200px"
            android:textSize="30px" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="密  码："
            android:textSize="60px"
            android:textColor="#FF0000" />
        <EditText
            android:id="@+id/editText2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:minWidth="200px"
            android:textSize="30px"
            android:inputType="textPassword" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="写 入"
            android:textSize="30px" />
        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="读 取"
            android:textSize="30px" />
    </LinearLayout>
</LinearLayout>

功能实现代码：

package com.example.administrator.denglujiemian;
public class  MainActivity extends AppCompatActivity {
    private EditText eveditText1;
    private EditText eveditText2;
    private Button button1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        eveditText1 = (EditText) findViewById(R.id.editText1);
        eveditText2 = (EditText) findViewById(R.id.editText2);
        button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String editText1 = eveditText1.getText().toString();
                String editText2 = eveditText2.getText().toString();
                Toast.makeText(MainActivity.this, "用户名：" + editText1 +
                        "密码" + editText2, Toast.LENGTH_LONG).show();
                if (saveToFile(editText1)) {
                    Toast.makeText(MainActivity.this, "保存成功", Toast.LENGTH_LONG).show();
                }
            }
        });
        button1 = (Button) findViewById(R.id.button1);
        eveditText1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String editText1 = eveditText1.getText().toString();
                String filename = "data.txt";
                String result = "";
                try {
                    FileInputStream in = openFileInput(filename);
                    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
                    editText1 = reader.readLine();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                editText1 = eveditText1.getText().toString();
                String editText2 = eveditText2.getText().toString();
                Toast.makeText(MainActivity.this, "用户名：" + editText1 + ",密码：" + editText2, Toast.LENGTH_SHORT).show();
            }
        });
    }
    private boolean saveToFile(String Name) {
        try {
            FileOutputStream out = openFileOutput("data.txt", MODE_PRIVATE);
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out));
            writer.write(Name);
            out.close();
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
}

效果