Android-根据按下的按钮添加到ListView

Question

I'm making an app and a part of it is adding a note to a listview (it's a simple meal planner app). I've been following a course on Lynda to implement it into my project ( Building a Note-Taking App for Android (2013) ).

I have got 3 ListViews and 3 Buttons on my activity and in my Java class. The ListViews in the Java class are named mLBMon, mLLMon, mLDMon (the B,L,D meaning breakfast, etc and the L meaning ListView, Mon just being Monday). And the Buttons use an OnClick in the XML, android:onClick="onClick". The onClick method is:

public void onClick(View v){
        MealItem meal = MealItem.getNew();
        Intent i = new Intent(this, MealEditor.class); // Meal Editor is the activity where the user enters the note which is displayed in the text view
        i.putExtra("key", meal.getKey());
        i.putExtra("text", meal.getText());
        startActivityForResult(i, 1001);
}

The ListView gets updated when the user returns back to the main page:

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == 1001 && resultCode == RESULT_OK){
            MealItem meal = new MealItem();
            meal.setKey(data.getStringExtra("key"));
            meal.setText(data.getStringExtra("text"));
            datasource.update(meal);
            refreshDisplay();
        }
    }

The refreshDisplay() :

private void refreshDisplay() {
        mealsList = datasource.findAll();
        ArrayAdapter<MealItem> adapter =
                new ArrayAdapter<MealItem>(this, R.layout.list_item_layout, mealsList);
        mLBMon.setAdapter(adapter);
    }

It seems that the mLBMon.setAdapater(adapter) determines which ListView it is presented on as when I change it to mLLMon or mLDMon it displays on the ListView.

So what I am trying to do is when a different button is clicked, it displays on the ListView "linked" to that button:

MondayLunchButton clicked -> User makes a note in the editor & presses back -> MondayLunchListView updated

etc.

It would be of great help if someone could guide me in the right direction and I would gladly provide more code if needed. This is my first time working with Android and I am trying to learn it so I decided to do a project so I am sorry if I have not provided enough info. Thanks.

Answer 1

For each button pressed send a different request code to MealEditor launching intent. When it will return back you will get exactly same id. Use this id to put a condition and update your ListView accordingly.

Do this

public void onClick(View v){
    MealItem meal = MealItem.getNew();
    Intent i = new Intent(this, MealEditor.class); // Meal Editor is the activity where the user enters the note which is displayed in the text view
    i.putExtra("key", meal.getKey());
    i.putExtra("text", meal.getText());
    if(v.getId() == R.id.breakfast) // use your breakfast button id here
        startActivityForResult(i, 1001); 
    else if(v.getId() == R.id.lunch) // use your lunch button id here
        startActivityForResult(i, 1002);
    else if(v.getId() == R.id.dinner) // use your dinner button id here
        startActivityForResult(i, 1003);
}

then

protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if ((requestCode == 1001 || requestCode == 1002 || requestCode == 1003) && resultCode == RESULT_OK){
        MealItem meal = new MealItem();
        meal.setKey(data.getStringExtra("key"));
        meal.setText(data.getStringExtra("text"));
        datasource.update(meal);
        refreshDisplay(requestCode);
    }
}

finally

private void refreshDisplay(int code) {
    mealsList = datasource.findAll();
    ArrayAdapter<MealItem> adapter =
            new ArrayAdapter<MealItem>(this, R.layout.list_item_layout, mealsList);
    if(code == 1001)
        mLBMon.setAdapter(adapter);
    else if(code == 1002)
        mLLMon.setAdapter(adapter);
    else if(code == 1003)
        mLDMon.setAdapter(adapter);
}

Note: Better to keep values like 1001 , 1002 and 1003 in a int constant such as CODE_BREAKFAST , CODE_LUNCH , CODE_DINNER ; so that you don't mess up the if-else condition by mistake.