Intent、Bundle

1、Intent封裝

public class IntentHelper {
    private Intent intent;
    private static IntentHelper intentHelper;
    private IntentHelper(){
        intent = new Intent();
    }

    public static IntentHelper getInstance(){
        if(intentHelper == null){
            intentHelper = new IntentHelper();
        }
        return intentHelper;
    }

    public Intent getIntent(Context packageContext, Class<?> cls){
        intent.setClass(packageContext, cls);
        return intent;
    }

    public Intent getIntentClearPreActivity(Context packageContext, Class<?> cls){
        Intent intent = new Intent();
        intent.setClass(packageContext, cls);
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        return intent;
    }

    public Intent getNewIntent(Context packageContext, Class<?> cls){
        Intent intentNew = new Intent();
        intentNew.setClass(packageContext, cls);
        return intentNew;
    }
}

2、Activity的兩種啓動模式：

FLAG.ACTIVITY_CLEAR_TOP
FLAG_ACTIVITY_REORDER_TO_FRONT

如果已經啓動了四個Activity：A，B，C，D 在D Activity裏，我們要跳轉到B Activity，同時希望C finish掉，可以在startActivity(intent)裏的intent裏添加flags標記

Intent intent = new Intent(this, B.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);

 

 這樣啓動B Activity，就會把D，C都finished掉，如果你的B Activity的啓動模式是默認的(multiple)，則B Activity會finished掉，再啓動一個新的Activity B。如果不想重新再創建一個新的B Activity，則在上面的代碼裏再加上

intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

 

3、bundle傳值

Intent intent = new Intent();
Bundle bundle = new Bundle();
bundle.putString("Tag", "mapView");
intent.setClass(A.this, B.class);
intent.putExtras(bundle);
startActivity(intent);

bundle = this.getIntent().getExtras();
bundle.getString("Tag");