Android编程心得-使用Application类保存应用的全局数据

在实际应用我们经常需要对数据进行交互与保存，但Intent中默认的方法对传输数据是有类型限制的，当我们需要传输或保存一个复杂的泛型数据时，使用Application是一个很好的解决办法。

顾名思义，Application对应整个应用，就如Activity对应当前的活动窗口一样，当我们需要使用它的时候，一定要在AndroidManifest.xml中对它进行声明。

[html] view plain copy print? <application
android:name=“MeterApplication”
android:allowBackup=“true”
android:icon=“@drawable/ic_launcher”
android:label=“@string/app_name”
android:theme=“@style/AppTheme” >
</application>

<application
android:name="MeterApplication"
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
</application>

然后我们来到实体类，首先当其他类需要存取或调用的时候，首先调用本类的getInstance()得到MeterApplication的对象，接下来就可以对不同类型的数据进行get,set操作了，这样形式的好处没有了一般数据类型的限制，当我们需要跨一个或多个Activity保存或者读取复杂数据的时候，问题就迎刃而解了。

调用方法： MeterApplication.getInstance().getXXX(); //读取

MeterApplication.getInstance().setXXX(X xxx);//存入

[java] view plain copy print?public class MeterApplication extends Application { private List<ReadyTask> DownloadList; private static MeterApplication instance; private HashMap<String, List<ReadyTask>> DownLoadResult; private List<String> UnitNumList; private String CurOPNUM; private boolean BlueConStatus; private int CurStauts; // 当前运行状态 @Override public void onCreate() { // TODO Auto-generated method stub instance = this; DownloadList = new ArrayList<ReadyTask>(); super.onCreate(); } public boolean isBlueConStatus() { return BlueConStatus; } public void setBlueConStatus(boolean blueConStatus) { BlueConStatus = blueConStatus; } public List<String> getUnitNumList() { return UnitNumList; } public void setUnitNumList(List<String> unitNumList) { UnitNumList = unitNumList; } public HashMap<String, List<ReadyTask>> getDownLoadResult() { return DownLoadResult; } public void setDownLoadResult(HashMap<String, List<ReadyTask>> downLoadResult) { DownLoadResult = downLoadResult; } public static MeterApplication getInstance() { return instance; } public List<ReadyTask> getDownloadList() { //下载List的值 return DownloadList; } public void setDownloadList(List<ReadyTask> downloadList) { DownloadList = downloadList; } public int getCurStauts() { return CurStauts; } public void setCurStauts(int curStauts) { CurStauts = curStauts; } public String getCurOPNUM() { return CurOPNUM; } public void setCurOPNUM(String curOPNUM) { CurOPNUM = curOPNUM; } }

public class MeterApplication extends Application {

private List<ReadyTask> DownloadList;
private static MeterApplication instance;

private HashMap<String, List<ReadyTask>> DownLoadResult;
private List<String> UnitNumList;
private String CurOPNUM;

private boolean BlueConStatus;

private int CurStauts;   // 当前运行状态
@Override
public void onCreate() {
// TODO Auto-generated method stub
instance = this;
DownloadList = new ArrayList<ReadyTask>();
super.onCreate();
}

public boolean isBlueConStatus() {
return BlueConStatus;
}

public void setBlueConStatus(boolean blueConStatus) {
BlueConStatus = blueConStatus;
}

public List<String> getUnitNumList() {
return UnitNumList;
}

public void setUnitNumList(List<String> unitNumList) {
UnitNumList = unitNumList;
}

public HashMap<String, List<ReadyTask>> getDownLoadResult() {
return DownLoadResult;
}

public void setDownLoadResult(HashMap<String, List<ReadyTask>> downLoadResult) {
DownLoadResult = downLoadResult;
}

public static MeterApplication getInstance() {
return instance;
}

public List<ReadyTask> getDownloadList() {   //下载List的值
return DownloadList;
}

public void setDownloadList(List<ReadyTask> downloadList) {
DownloadList = downloadList;
}

public int getCurStauts() {
return CurStauts;
}

public void setCurStauts(int curStauts) {
CurStauts = curStauts;
}

public String getCurOPNUM() {
return CurOPNUM;
}

public void setCurOPNUM(String curOPNUM) {
CurOPNUM = curOPNUM;
}

}