图片拖拽演示.zip

package com.hzq.picturedraganddropdemo; import android.Manifest; import android.content.Intent; import android.content.pm.PackageManager; import android.graphics.Canvas; import android.net.Uri; import android.os.Build; import android.os.Bundle; import android.provider.MediaStore; import android.text.TextUtils; import android.util.Log; import android.view.View; import android.view.animation.AccelerateInterpolator; import android.widget.TextView; import com.hzq.picturedraganddropdemo.adapter.GridImageAdapter; import java.util.ArrayList; import java.util.Collections; import androidx.annotation.NonNull; import androidx.annotation.Nullable; import androidx.appcompat.app.AppCompatActivity; import androidx.core.app.ActivityCompat; import androidx.core.content.ContextCompat; import androidx.recyclerview.widget.GridLayoutManager; import androidx.recyclerview.widget.ItemTouchHelper; import androidx.recyclerview.widget.RecyclerView; /** * @author 小强 * @time 2020/4/20 09:00 * @desc 主页(演示图片拖拽) */ public class MainActivity extends AppCompatActivity implements GridImageAdapter.onAddPicClickListener { private ItemTouchHelper mItemTouchHelper; private DragListener mDragListener; private boolean needScaleBig = true; private boolean needScaleSmall = true; private RecyclerView mRecyclerView; private TextView mTvDeleteText; private boolean isUpward; private GridImageAdapter mAdapter; private int maxSelectNum = 9; public static final int RC_CHOOSE_PHOTO = 1; ArrayList<String> strings = new ArrayList<>(); @Override protected void onCreate (@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mRecyclerView = findViewById(R.id.recycler); mTvDeleteText = findViewById(R.id.tv_delete_text); FullyGridLayoutManager manager = new FullyGridLayoutManager(this, 4, GridLayoutManager.VERTICAL, false); mRecyclerView.setLayoutManager(manager); mAdapter = new GridImageAdapter(this, this); mAdapter.setList(strings); mAdapter.setSelectMax(maxSelectNum); mRecyclerView.setAdapter(mAdapter); mAdapter.setItemLongClickListener((holder, position, v) -> { //如果item不是最后一个，则执行拖拽 needScaleBig = true; needScaleSmall = true; int size = mAdapter.getData().size(); if (size != maxSelectNum) { mItemTouchHelper.startDrag(holder); return; } if (holder.getLayoutPosition() != size - 1) { mItemTouchHelper.startDrag(holder); } }); mDragListener = new DragListener() { @Override public void deleteState (boolean isDelete) { if (isDelete) { mTvDeleteText.setText("松手即可删除"); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) { mTvDeleteText.setCompoundDrawablesRelativeWithIntrinsicBounds(0, R.mipmap.icon_let_go_delete, 0, 0); } } else { mTvDeleteText.setText("拖动到此处删除"); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) { mTvDeleteText.setCompoundDrawablesRelativeWithIntrinsicBounds(0, R.mipmap.picture_icon_delete, 0, 0); } } } @Override public void dragState (boolean isStart) { int visibility = mTvDeleteText.getVisibility(); if (isStart) { if (visibility == View.GONE) { mTvDeleteText.animate().alpha(1).setDuration(300).setInterpolator(new AccelerateInterpolator()); mTvDeleteText.setVisibility(View.VISIBLE); } } else { if (visibility == View.VISIBLE) { mTvDeleteText.animate().alpha(0).setDuration(300).setInterpolator(new AccelerateInterpolator()); mTvDeleteText.setVisibility(View.GONE); } } } }; mItemTouchHelper = new ItemTouchHelper(new ItemTouchHelper.Callback() { @Override public boolean isLongPressDragEnabled () { return true; } @Override public void onSwiped (@NonNull RecyclerView.ViewHolder viewHolder, int direction) { } @Override public int getMovementFlags (@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder) { int itemViewType = viewHolder.getItemViewType(); if (itemViewType != GridImageAdapter.TYPE_CAMERA) { viewHolder.itemView.setAlpha(0.7f); } return makeMovementFlags(ItemTouchHelper.DOWN | ItemTouchHelper.UP | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT, 0); } @Override public boolean onMove (@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) { //得到item原来的position try { int fromPosition = viewHolder.getAdapterPosition(); //得到目标position int toPosition = target.getAdapterPosition(); int itemViewType = target.getItemViewType(); if (itemViewType != GridImageAdapter.TYPE_CAMERA) { if (fromPosition < toPosition) { for (int i = fromPosition; i < toPosition; i++) { Collections.swap(mAdapter.getData(), i, i + 1); } } else { for (int i = fromPosition; i > toPosition; i--) { Collections.swap(mAdapter.getData(), i, i - 1); } } mAdapter.notifyItemMoved(fromPosition, toPosition); } } catch (Exception e) { e.printStackTrace(); } return true; } @Override public void onChildDraw (@NonNull Canvas c, @NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) { int itemViewType = viewHolder.getItemViewType(); if (itemViewType != GridImageAdapter.TYPE_CAMERA) { if (null == mDragListener) { return; } if (needScaleBig) { //如果需要执行放大动画 viewHolder.itemView.animate().scaleXBy(0.1f).scaleYBy(0.1f).setDuration(100); //执行完成放大动画,标记改掉 needScaleBig = false; //默认不需要执行缩小动画，当执行完成放大 并且松手后才允许执行 needScaleSmall = false; } int sh = recyclerView.getHeight() + mTvDeleteText.getHeight(); int ry = mTvDeleteText.getTop() - sh; if (dY >= ry) { //拖到删除处 mDragLis