学习目的：文件存储
将数据保存到文件
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70public void save(String inputText) {
FileOutputStream out = null;
BufferedWriter writer = null;
try {
out = openFileOutput("data", Context.MODE_PRIVATE);//MODE_PRIVATE指定同一文件名将被覆盖 openFileOutput（）获得FileOutputSteame对象 再借助它构建OutputStreamWriter对象 再使用OutputStreamWriter构建BufferedWriter对象
writer = new BufferedWriter(new OutputStreamWriter(out));//
writer.write(inputText);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (writer != null) {
writer.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
```
- 范例
```java
public class MainActivity extends AppCompatActivity {
private EditText edit;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
edit = (EditText) findViewById(R.id.edit);
}
protected void onDestroy() {
super.onDestroy();
String inputText = edit.getText().toString();
save(inputText);//掉用自定义方法 存储输入字符
}
```
- 从文件中读取数据
```java
public String load() {
FileInputStream in = null;
BufferedReader reader = null;
StringBuilder content = new StringBuilder();
try {
in = openFileInput("data");//获取FileInputStream对象data
reader = new BufferedReader(new InputStreamReader(in));构建InputStreamReader对象reader
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();
}范例
public class MainActivity extends AppCompatActivity { private EditText edit; protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); edit = (EditText) findViewById(R.id.edit); String inputText = load(); if (!TextUtils.isEmpty(inputText)) { edit.setText(inputText); edit.setSelection(inputText.length()); Toast.makeText(this, "Restoring succeeded", Toast.LENGTH_SHORT).show(); } }