Question

我的应用中有一个用于每个活动的图像按钮。我需要在按下图像按钮时转到主屏幕。我正在使用代码

btnLocation.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               // Intent intent=new Intent(SpecificCategoryActivity.this,AreaSelectionActivity.class);

                //startActivity(intent);
                Intent homeIntent = new Intent(SpecificCategoryActivity.this, AreaSelectionActivity.class);
                homeIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(homeIntent);

            }
        });

但是，当我点击图片按钮后从主屏幕导航时，它应该从它呼叫的地方转到同一页面。

例如，我有Activity1，Activity2，Activity3，Activity4等...... Activity1是主页，我将选择country并转到Activity2然后转到Activity3，依此类推，但是如果我点击Activity4中的Location按钮，它应该转到主页，在更改国家后它必须回到Activity4.And还有一件事是，如果已选择国家/地区应用程序将从Activity2启动。

我的Activity1代码是

btnStart.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


            if(!autoComplete.getText().toString().isEmpty()) {

                if (isSelectedText) {


                    Intent intent = new Intent(CountrySelectionActivity.this, CategoryListActvity.class);
                     startActivity(intent);


                }
                else{
                    editor.clear();
                    editor.commit(); // commit changes
                    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(CountrySelectionActivity.this);

                    alertDialogBuilder.setMessage("Please specify the correct country name");

                    AlertDialog alertDialog = alertDialogBuilder.create();
                    alertDialog.show();

                }
            }


        }
    });

请帮助解决问题。提前致谢。

Answer 1

I will give some pseudo code here
    In Activity4, locationbutton onclick listener will have the below code
    locationbutton .setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

       //save a variable to indicate that activity4 is reached
    savePreferences("**pagenavigated**", "4", context);  //need to write //savePreferences

     Intent intent = new Intent(activity4.this, homepage.class);
                         startActivity(intent);

        });
    //We can write this method commonly so all activity can access this
    public static void savePreferences(String key, String value, Context context) {

            SharedPreferences SharedPreferences = PreferenceManager
                    .getDefaultSharedPreferences(context);
            SharedPreferences.Editor editor = SharedPreferences.edit();
            editor.putString(key, value);
            editor.commit();
        }
    public static String loadPreferences(Context context, String key) {
            SharedPreferences SharedPreferences = PreferenceManager
                    .getDefaultSharedPreferences(context);
            String userDetails = SharedPreferences.getString(key, "");
            return userDetails;

        }
public static void removePreference(String key, Context context) {

        SharedPreferences SharedPreferences = PreferenceManager
                .getDefaultSharedPreferences(context);
        SharedPreferences.Editor editor = SharedPreferences.edit();
        editor.remove(key);
        editor.commit();

    }

    public static void removeAllPreferences(Context context) {

        SharedPreferences SharedPreferences = PreferenceManager
                .getDefaultSharedPreferences(context);
        SharedPreferences.Editor editor = SharedPreferences.edit();
        editor.clear();
        editor.commit();

    }
//In Activity 1, check for sharedpreference variable value and if it is 4, it //should get navigate to 4th screen . To make this happen , after checking //the value, we need to remove the shared value as well
//Activity 1
//In **country dropdown change listener**, check for the value of //**pagenavigated** and if it is 4, start the activity to go for activity 4. //Before that remove the value by using removeAllPreferences method
//So changes will be in onItemSelected
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String navigatedPage = loadPreferences(context,"pagenavigated");
if (navigatedPage.equalsIgnoreCase("4") {
removeAllPreferences(this);  //Remove the preference and go to activity 4)
Intent intent = new Intent(homepage.this, activity4.class);
                         startActivity(intent);
}



Hope that helps!!!

Answer 2

在这里你可以使用 startActivityForResult（Intent intent，int resultCode）;

e.g

 Intent intent = new Intent(CountrySelectionActivity.this, CategoryListActvity.class);
    intent.putExtra("Select_Location", true);
    startActivityForResult(intent,007);

现在在第一次活动中检查意图数据，如果您将“ Select_Location ”标记为true，那么在选择城市后，请调用finish（）;

e.g。

在活动1的onCreate方法

Intent i=getIntent(); //**i** will be null if Activity is called from another Activity

if(i!=null)
    boolean flag=i.getBooleanExtra("Select_Location", false);
    //now you have flag which indicates that whether this intent is from 4th activity or not.

让用户选择城市，在onClick方法中只检查我们的标志是否为真。

如果是真的那么只需使用意图并附上所有必需的信息并调用完成。

e.g

Intent resultIntent = new Intent();
resultIntent.putExtra("city_id", <city id>);
...
setResult(Activity.RESULT_OK, resultIntent);
finish();

现在你需要覆盖名为 onActivityResult 的方法（在活动4中）

e.g。

@Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            if (resultCode == RESULT_OK && requestCode == 007 && data != null){
       // take out all the parameters from data(which is an object of Intent).

            }
    }

单击操作栏按钮时转到主屏幕

2 个答案: