Question

我是Android新手，一直在线查看教程。我正在寻找一个具有可滚动界面的gridview，但是，我希望将其实现为片段而不是活动，如果没有扩展的AppCompatActivity，它就无法工作，因此寻找有关如何使用片段进行构建的建议。

以下是使用扩展AppCompatActivity的活动中gridview的代码。

public class MainActivity extends AppCompatActivity {

    GridLayout mainGrid;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mainGrid = (GridLayout) findViewById(R.id.mainGrid);

        //Set Event
        setSingleEvent(mainGrid);
        //setToggleEvent(mainGrid);
    }

    private void setToggleEvent(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
            final CardView cardView = (CardView) mainGrid.getChildAt(i);
            cardView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    if (cardView.getCardBackgroundColor().getDefaultColor() == -1) {
                        //Change background color
                        cardView.setCardBackgroundColor(Color.parseColor("#FF6F00"));
                        Toast.makeText(MainActivity.this, "State : True", Toast.LENGTH_SHORT).show();

                    } else {
                        //Change background color
                        cardView.setCardBackgroundColor(Color.parseColor("#FFFFFF"));
                        Toast.makeText(MainActivity.this, "State : False", Toast.LENGTH_SHORT).show();
                    }
                }
            });
        }
    }

    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) {

                    Intent intent = new Intent(MainActivity.this,ActivityOne.class);
                    intent.putExtra("info","This is activity from card item index  "+finalI);
                    startActivity(intent);

                }
            });
        }
    }

这是我到目前为止尝试将其与片段集成时所尝试的。

 public class DashboardFragment extends Fragment {

GridLayout mainGrid;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    return inflater.inflate(R.layout.fragment_dashboard, container,false);


        mainGrid = (GridLayout) findViewById(R.id.mainGrid);

        //Set Event
        setSingleEvent(mainGrid);
        //setToggleEvent(mainGrid);
    }

    private void setToggleEvent(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
            final CardView cardView = (CardView) mainGrid.getChildAt(i);
            cardView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    if (cardView.getCardBackgroundColor().getDefaultColor() == -1) {
                        //Change background color
                        cardView.setCardBackgroundColor(Color.parseColor("#FF6F00"));
                        Toast.makeText(MainActivity.this, "State : True", Toast.LENGTH_SHORT).show();

                    } else {
                        //Change background color
                        cardView.setCardBackgroundColor(Color.parseColor("#FFFFFF"));
                        Toast.makeText(MainActivity.this, "State : False", Toast.LENGTH_SHORT).show();
                    }
                }
            });
        }
    }

    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) {

                    Intent intent = new Intent(MainActivity.this,ActivityOne.class);
                    intent.putExtra("info","This is activity from card item index  "+finalI);
                    startActivity(intent);

                }
            });
        }
    }
}

显示错误

error part 1

error part 2

Answer 1

我认为您将面临编译时错误，因为在您的片段的onCreateView()方法中返回膨胀的视图之前，您必须完成其他工作，如下所示：

public class DashboardFragment extends Fragment {

GridLayout mainGrid;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_dashboard, container,false);


        mainGrid = (GridLayout) view.findViewById(R.id.mainGrid);

        //Set Event
        setSingleEvent(mainGrid);
     return view;
    }

    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) {

                    Intent intent = new Intent(getActivity(),ActivityOne.class);
                    intent.putExtra("info","This is activity from card item index  "+finalI);
                    startActivity(intent);

                }
            });
        }
    }
}

注意： - 请确保您已为CardView添加了相关性在这样的build.gradle文件中。

dependencies {
    implementation 'com.android.support:cardview-v7:27.1.1'
}

在Android中的片段中创建可滚动的网格视图

1 个答案: