Cardview 多项活动

Question

I working on Android studio 3.0.1. I working a project on android cardview. I see a video tutorial on android cardview. I write code carefully. But when I run code, it saw some error.

Here's the corresponding code in my MainActivity.java

private void setSingleEvent(GridLayout mainGrid) {
    //Loop all child item of Main Grid
    for (int i = 0; i < mainGrid.getChildCount(); i++) {
        //You can see , all child item is CardView , so we just cast object to CardView
        CardView cardView = (CardView) mainGrid.getChildAt(i);
        final int finalI = i;
        cardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (finalI == 0) //Teachers Activities
                {
                    Intent intent = new Intent( packageContext: MainActivity.this, Teachers.class);
                    startActivity(intent);
                }

                else if (finalI == 1) //Students Activities
                {
                    Intent intent = new Intent( packageContext: MainActivity.this, Students.class);
                    startActivity(intent);
                }
                else if (finalI == 2) //Students Activities
                {
                    Intent intent = new Intent( packageContext: MainActivity.this, Students.class);
                    startActivity(intent);
                }
                else if (finalI == 3) //Notices Activities
                {
                    Intent intent = new Intent( packageContext: MainActivity.this, Notices.class);
                    startActivity(intent);
                }
                else if (finalI == 4) //Results Activities
                {
                    Intent intent = new Intent( packageContext: MainActivity.this, Results.class);
                    startActivity(intent);
                }
                else if (finalI == 5) //Phones Activities
                {
                    Intent intent = new Intent( packageContext: MainActivity.this, Phones.class);
                    startActivity(intent);
                }
                else if (finalI == 6) //Blood Activities
                {
                    Intent intent = new Intent( packageContext: MainActivity.this, Bloods.class);
                    startActivity(intent);
                }
                else {
                    Toast.makeText(MainActivity.this, "Activvvv", Toast.LENGTH_SHORT).show();
                }


            }
        });
    }
}

Full Source code on here

Answer 1

Remove the packageContext which are red. The final function should look like this.

private void setSingleEvent(GridLayout mainGrid) {
    //Loop all child item of Main Grid
    for (int i = 0; i < mainGrid.getChildCount(); i++) {
        //You can see , all child item is CardView , so we just cast object to CardView
        CardView cardView = (CardView) mainGrid.getChildAt(i);
        final int finalI = i;
        cardView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (finalI == 0) //Teachers Activities
                {
                    Intent intent = new Intent(MainActivity.this, Teachers.class);
                    startActivity(intent);
                }

                else if (finalI == 1) //Students Activities
                {
                    Intent intent = new Intent(MainActivity.this, Students.class);
                    startActivity(intent);
                }
                else if (finalI == 2) //Students Activities
                {
                    Intent intent = new Intent(MainActivity.this, Students.class);
                    startActivity(intent);
                }
                else if (finalI == 3) //Notices Activities
                {
                    Intent intent = new Intent(MainActivity.this, Notices.class);
                    startActivity(intent);
                }
                else if (finalI == 4) //Results Activities
                {
                    Intent intent = new Intent(MainActivity.this, Results.class);
                    startActivity(intent);
                }
                else if (finalI == 5) //Phones Activities
                {
                    Intent intent = new Intent(MainActivity.this, Phones.class);
                    startActivity(intent);
                }
                else if (finalI == 6) //Blood Activities
                {
                    Intent intent = new Intent(MainActivity.this, Bloods.class);
                    startActivity(intent);
                }
                else {
                    Toast.makeText(MainActivity.this, "Activvvv", Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

Answer 2

Android Studio complains because the following statement is syntactically wrong in Java:

Intent intent = new Intent( packageContext: MainActivity.this, Notices.class);

Android Studio shows parameter names (like "packageContext:") before method parameters to give Java code for Android a bit of a Kotlin look and feel. This can be confusing for beginners. The correct form of the statement is:

Intent intent = new Intent(MainActivity.this, Notices.class);