爲什麼我的RecyclerView項目之間的空間不一樣？

Question

我用ItemDecoration設置網格RecyclerView項目之間的空間，我想每個項目之間的間隔相等。

ItemDecoration

public class SpaceItemDecoration extends RecyclerView.ItemDecoration { 
private int space; 
public SpaceItemDecoration(int space) { 
    this.space = space; 
} 
@Override 
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) { 
    if (parent.getLayoutManager() instanceof GridLayoutManager) { 
     GridLayoutManager.LayoutParams layoutParams = (GridLayoutManager.LayoutParams) view.getLayoutParams(); 
     GridLayoutManager gridLayoutManager = (GridLayoutManager) parent.getLayoutManager(); 
     int spanSize = layoutParams.getSpanSize(); 
     int spanIndex = layoutParams.getSpanIndex(); 
     int totalSpanSize = gridLayoutManager.getSpanCount(); 
     if (spanIndex == 0) {//left 
      outRect.left = space; 
      outRect.right = space/2; 
     } else if (spanSize + spanIndex == totalSpanSize) {//right 
      outRect.right = space; 
      outRect.left = space/2; 
     } else if (spanIndex > 0 && spanSize + spanIndex < totalSpanSize) { 
      outRect.left = space/2; 
      outRect.right = space/2; 
     } 
     outRect.bottom = space; 
    } 
} 

RecyclerView

<android.support.v7.widget.RecyclerView 
      android:id="@+id/recyclerview" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_gravity="center"/> 

項目XML

<LinearLayout 
xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="90dp" 
android:layout_height="90dp" 
android:background="#ff6600" 
android:orientation="vertical"> 

</LinearLayout> 

Answer 1

試試這個，

int spanCount; 
final private Context mContext =YourActivity.this; 

@Override 
protected void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    setContentView(R.layout.activity_login); 
    recycler_view=(RecyclerView)findViewById(R.id.recycler_view); 

    recycler_view.setLayoutManager(new GridLayoutManager(mContext, 2)); 
    if (value == Configuration.ORIENTATION_PORTRAIT) { 
     spanCount = 2; 
    } 
    else if (value == Configuration.ORIENTATION_LANDSCAPE) { 
     spanCount = 3; 
    } 
    int spacing_left = 50; // 50px 
    int spacing_top=10; 

    recycler_view.addItemDecoration(new GridSpacingItemDecoration(spanCount, spacing_left, spacing_top)); 
} 

@Override 
protected void onResume() { 

    value = activity.getResources().getConfiguration().orientation; 

    if (value == Configuration.ORIENTATION_PORTRAIT) { 
     spanCount = 2; 
    } 
    else if (value == Configuration.ORIENTATION_LANDSCAPE) { 
     spanCount = 3; 
    } 

    super.onResume(); 
} 

GridSpacingItemDecoration：

/* set spacing for grid view */ 
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration 
{ 
    final private int spanCount,spacing,spacing_top; 
    final private boolean includeEdge; 

    public GridSpacingItemDecoration(int spanCount, int spacing_left, int spacing_top) 
    { 
     this.spanCount = spanCount; 
     this.spacing = spacing_left; 
     this.includeEdge = true; 
     this.spacing_top=spacing_top; 
    } 

    @Override 
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) 
    { 
     int position = parent.getChildAdapterPosition(view); // item phases_position 
     int column = position % spanCount; // item column 

     if (includeEdge) 
     { 
      outRect.left = spacing - column * spacing/spanCount; // spacing - column * ((1f/spanCount) * spacing) 
      outRect.right = (column + 1) * spacing/spanCount; // (column + 1) * ((1f/spanCount) * spacing) 

      if (position < spanCount) 
      { // top edge 
       outRect.top = spacing_top; 
      } 
      outRect.bottom = spacing_top; // item bottom 
     } 
     else 
     { 
      outRect.left = column * spacing/spanCount; // column * ((1f/spanCount) * spacing) 
      outRect.right = spacing - (column + 1) * spacing/spanCount; // spacing - (column + 1) * ((1f/ spanCount) * spacing) 
      if (position >= spanCount) 
      { 
       outRect.top = spacing_top; // item top 
      } 
     } 
    } 
} 

Answer 2

你爲什麼不嘗試刪除代碼，自定義間隔，並利用電網參數的android：horizo​​ntalSpacing和android：verticalSpacing？

Answer 3

添加android:scaleType="fitXY"您的項目XML中，這將擴大使用FILL讓所有的物品佔據同一區域的圖像。

Answer 4

使用GridItemDecoration：

import android.content.Context; 
import android.graphics.Rect; 
import android.support.annotation.DimenRes; 
import android.support.annotation.NonNull; 
import android.support.v7.widget.RecyclerView; 
import android.view.View; 

public class GridItemDecoration extends RecyclerView.ItemDecoration { 

    private int mItemOffset; 

    public GridItemDecoration(int itemOffset) { 
     mItemOffset = itemOffset; 
    } 

    public GridItemDecoration(@NonNull Context context, @DimenRes int itemOffsetId) { 
     this(context.getResources().getDimensionPixelSize(itemOffsetId)); 
    } 

    @Override 
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, 
           RecyclerView.State state) { 
     super.getItemOffsets(outRect, view, parent, state); 
     outRect.set(mItemOffset, mItemOffset, mItemOffset, mItemOffset); 
    } 
} 

從你Activity：

RecyclerView mRecyclerView; 
RecyclerView.LayoutManager mLayoutManager; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    ................ 
    ........................ 

    mRecyclerView = (RecyclerView) findViewById(R.id.recyclerview); 

    mRecyclerView.setHasFixedSize(true); 

    // Grid layout manager 
    mLayoutManager = new GridLayoutManager(mContext, 3); // spanCount = 3 for 3 columns 
    mRecyclerView.setLayoutManager(mLayoutManager); 

    // Grid item spacing 
    GridItemDecoration itemDecoration = new GridItemDecoration(mContext, R.dimen.grid_item_spacing); // R.dimen.grid_item_spacing is 2dp 
    mRecyclerView.addItemDecoration(itemDecoration); 

    ............ 
    ...................... 
}