关于如何保存activity被意外销毁（被意外你懂的，这个大师，那个助手的，还有那什么...）的状态数据，有多重方式，比如持久化了，还有如下这种方式：
package com.suchangli.demo;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity{
private String mStatu;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//恢复数据
if(savedInstanceState ！= null){
mStatu = savedInstanceState.getString("statu");
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putString("mStatu", mStatu);
}
//也可以在这里恢复数据
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
mStatu = savedInstanceState.getString("statu");
}
}感觉很熟悉对吧，但是如果变量多了，或者是很多Activity都需要保存数据，是不是感觉特别的屎啊，那么问题来了，哪种方式比较好？
请看下面的实现方式，把这种方式写到基类里面，让所有的Activity继承这个基类
package com.suchangli.demo;
import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Field;
import android.app.Activity;
import android.os.Bundle;
import android.os.Parcelable;
/**
* 定义一个注解@SavedInstanceState，用于修饰需要保存的状态， 对于用这个注解修饰的变量或者状态，保存恢复就可以了。
* 子类如果想保存某个字段的状态，只需要用这个注解修饰就可以了
*
* @author tempadmin
*
*/
public class BaseActivity extends Activity {
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface SavedInstanceState {
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// 恢复数据
if (savedInstanceState ！= null) {
restoreInstanceState(savedInstanceState);
}
}
/**
* 保存状态
*/
@Override
protected void onSaveInstanceState(Bundle outState) {
Field[] fields = this.getClass().getDeclaredFields();
Field.setAccessible(fields, true);
Annotation[] ans;
for (Field f : fields) {
ans = f.getDeclaredAnnotations();
for (Annotation an : ans) {
if (an instanceof SavedInstanceState) {
try {
Object o = f.get(this);
if (o == null) {
continue;
}
String fieldName = f.getName();
if (o instanceof Integer) {
outState.putInt(fieldName, f.getInt(this));
} else if (o instanceof String) {
outState.putString(fieldName, (String) f.get(this));
} else if (o instanceof Long) {
outState.putLong(fieldName, f.getLong(this));
} else if (o instanceof Short) {
outState.putShort(fieldName, f.getShort(this));
} else if (o instanceof Boolean) {
outState.putBoolean(fieldName, f.getBoolean(this));
} else if (o instanceof Byte) {
outState.putByte(fieldName, f.getByte(this));
} else if (o instanceof Character) {
outState.putChar(fieldName, f.getChar(this));
} else if (o instanceof CharSequence) {
outState.putCharSequence(fieldName,
(CharSequence) f.get(this));
} else if (o instanceof Float) {
outState.putFloat(fieldName, f.getFloat(this));
} else if (o instanceof Double) {
outState.putDouble(fieldName, f.getDouble(this));
} else if (o instanceof String[]) {
outState.putStringArray(fieldName,
(String[]) f.get(this));
} else if (o instanceof Parcelable) {
outState.putParcelable(fieldName,
(Parcelable) f.get(this));
} else if (o instanceof Serializable) {
outState.putSerializable(fieldName,
(Serializable) f.get(this));
} else if (o instanceof Bundle) {
outState.putBundle(fieldName, (Bundle) f.get(this));
}
} catch (IllegalArgumentException e) {
} catch (IllegalAccessException e) {
} catch (Exception e) {
}
}
}
}
super.onSaveInstanceState(outState);
}
/**
* 在这里恢复数据
* @param savedInstanceState
*/
private void restoreInstanceState(Bundle savedInstanceState) {
Field[] fields = this.getClass().getDeclaredFields();
Field.setAccessible(fields, true);
Annotation[] ans;
for (Field f : fields) {
ans = f.getDeclaredAnnotations();
for (Annotation an : ans) {
if (an instanceof SavedInstanceState) {
try {
String fieldName = f.getName();
Class cls = f.getType();
if (cls == int.class || cls == Integer.class) {
f.setInt(this, savedInstanceState.getInt(fieldName));
} else if (String.class.isAssignableFrom(cls)) {
f.set(this, savedInstanceState.getString(fieldName));
} else if (Serializable.class.isAssignableFrom(cls)) {
f.set(this, savedInstanceState.getSerializable(fieldName));
} else if (cls == long.class || cls == Long.class) {
f.setLong(this, savedInstanceState.getLong(fieldName));
} else if (cls == short.class || cls == Short.class) {
f.setShort(this, savedInstanceState.getShort(fieldName));
} else if (cls == boolean.class || cls == Boolean.class) {
f.setBoolean(this, savedInstanceState.getBoolean(fieldName));
} else if (cls == byte.class || cls == Byte.class) {
f.setByte(this, savedInstanceState.getByte(fieldName));
} else if (cls == char.class || cls == Character.class) {
f.setChar(this, savedInstanceState.getChar(fieldName));
} else if (CharSequence.class.isAssignableFrom(cls)) {
f.set(this, savedInstanceState.getCharSequence(fieldName));
} else if (cls == float.class || cls == Float.class) {
f.setFloat(this, savedInstanceState.getFloat(fieldName));
} else if (cls == double.class || cls == Double.class) {
f.setDouble(this, savedInstanceState.getDouble(fieldName));
} else if (String[].class.isAssignableFrom(cls)) {
f.set(this, savedInstanceState.getStringArray(fieldName));
} else if (Parcelable.class.isAssignableFrom(cls)) {
f.set(this, savedInstanceState.getParcelable(fieldName));
} else if (Bundle.class.isAssignableFrom(cls)) {
f.set(this, savedInstanceState.getBundle(fieldName));
}
} catch (IllegalArgumentException e) {
} catch (IllegalAccessException e) {
} catch (Exception e) {
}
}
}
}
}
}这样就ok了，以后妈妈再也不用关心怎么保存状态了，就是这么任性。。。。
贡献者：Com360