安卓实战：记事本应用开发

【实例截图】

package com.example.biji; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.content.SharedPreferences; import android.database.sqlite.SQLiteDatabase; import android.graphics.Color; import android.graphics.drawable.ColorDrawable; import android.media.Image; import android.os.Bundle; import android.preference.PreferenceManager; import android.util.DisplayMetrics; import android.util.Log; import android.view.Gravity; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.WindowManager; import android.widget.AdapterView; import android.widget.ImageView; import android.widget.ListView; import android.widget.PopupWindow; import android.widget.RelativeLayout; import android.widget.TextView; import androidx.appcompat.app.AlertDialog; import androidx.appcompat.widget.SearchView; import androidx.appcompat.widget.Toolbar; import com.google.android.material.floatingactionbutton.FloatingActionButton; import com.test.greendaodemo.NoteDao; import java.util.ArrayList; import java.util.List; public class MainActivity extends BaseActivity implements AdapterView.OnItemClickListener { //NoteDao mNoteDao = MyApplication.getInstances().getDaoSession().getNoteDao();  private NoteDatabase dbHelper; private Context context = this; final String TAG = "tag";
    FloatingActionButton btn; private ListView lv; private NoteAdapter adapter; private List<Note> noteList = new ArrayList<Note>(); private Toolbar myToolbar; private NoteDao noteDao; public NoteDao getNoteDao() { return noteDao;
    } //弹出菜单  private PopupWindow popupWindow; private PopupWindow popupCover; private ViewGroup customView; private ViewGroup coverView; private LayoutInflater layoutInflater; private RelativeLayout main; private WindowManager wm; private DisplayMetrics metrics; private TextView setting_text; private ImageView setting_image; @Override  protected void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initPrefs(); btn = (FloatingActionButton) findViewById(R.id.fab); lv = (ListView) findViewById(R.id.lv); myToolbar = findViewById(R.id.myToolbar); adapter = new NoteAdapter(getApplicationContext(), noteList);
        refreshListView(); lv.setAdapter(adapter);

        setSupportActionBar(myToolbar);
        getSupportActionBar().setHomeButtonEnabled(true);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true); //设置toolbar取代actionbar  initPopUpView(); myToolbar.setNavigationIcon(R.drawable.ic_menu_black_24dp); myToolbar.setNavigationOnClickListener(new View.OnClickListener() { @Override  public void onClick(View v) {
                Log.d(TAG, "onClick: menu");
                showPopUpView();
            }
        }); lv.setOnItemClickListener(this); btn.setOnClickListener(new View.OnClickListener() { @Override  public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, EditActivity.class);
                intent.putExtra("mode", 4);
                startActivityForResult(intent, 0);
            }
        });

    } public void initPopUpView(){ layoutInflater = (LayoutInflater) MainActivity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE); customView = (ViewGroup) layoutInflater.inflate(R.layout.setting_layout, null); coverView = (ViewGroup) layoutInflater.inflate(R.layout.setting_cover, null); main = findViewById(R.id.main_layout); wm = getWindowManager(); metrics = new DisplayMetrics(); wm.getDefaultDisplay().getMetrics(metrics);
    } public void showPopUpView(){ int width = metrics.widthPixels; int height = metrics.heightPixels; popupCover = new PopupWindow(coverView, width, height, false); popupWindow = new PopupWindow(customView, (int) (width * 0.67), height, true); popupWindow.setBackgroundDrawable(new ColorDrawable(Color.WHITE)); //在主界面加载成功之后 显示弹出  findViewById(R.id.main_layout).post(new Runnable() { @Override  public void run() { popupCover.showAtLocation(main, Gravity.NO_GRAVITY, 0, 0); popupWindow.showAtLocation(main, Gravity.NO_GRAVITY, 0, 0); setting_image = customView.findViewById(R.id.setting_settings_image); setting_text = customView.findViewById(R.id.setting_settings_text); setting_image.setOnClickListener(new View.OnClickListener() { @Override  public void onClick(View v) {
                        startActivity(new Intent(MainActivity.this, UserSettingsActivity.class));
                    }
                }); setting_text.setOnClickListener(new View.OnClickListener() { @Override  public void onClick(View v) {
                        startActivity(new Intent(MainActivity.this, UserSettingsActivity.class));
                    }
                }); coverView.setOnTouchListener(new View.OnTouchListener() { @Override  public boolean onTouch(View v, MotionEvent event) { popupWindow.dismiss(); return true;
                    }
                }); popupWindow.setOnDismissListener(new PopupWindow.OnDismissListener() { @Override  public void onDismiss() { popupCover.dismiss();
                        Log.d(TAG, "onDismiss: test");
                    }
                });
            }

        });

    } public void initPrefs(){
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
        SharedPreferences.Editor editor = sharedPreferences.edit(); if (!sharedPreferences.contains("nightMode")) {
            editor.putBoolean("nightMode", false);
            editor.commit();
        }
    } // 接受startActivityForResult的结果  @Override  protected void onActivityResult(int requestCode, int resultCode, Intent data){ int returnMode; long note_Id;
        returnMode = data.getExtras().getInt("mode", -1);
        note_Id = data.getExtras().getLong("id", 0); if (returnMode == 1) { //update current note   String content = data.getExtras().getString("content");
            String time = data.getExtras().getString("time"); int tag = data.getExtras().getInt("tag", 1);

            Note newNote = new Note(content, time, tag);
            newNote.setId(note_Id);
            CRUD op = new CRUD(context);
            op.open();
            op.updateNote(newNote);
            op.close();
        } else if (returnMode == 0) { // create new note  String content = data.getExtras().getString("content");
            String time = data.getExtras().getString("time"); int tag = data.getExtras().getInt("tag", 1);

            Note newNote = new Note(content, time, tag);
            CRUD op = new CRUD(context);
            op.open();
            op.addNote(newNote);
            op.close();
        } else if (returnMode == 2) { // delete  Note curNote = new Note();
            curNote.setId(note_Id);
            CRUD op = new CRUD(context);
            op.open();
            op.removeNote(curNote);
            op.close();
        } else{

        }
        refreshListView(); super.onActivityResult(requestCode, resultCode, data);

    } @Override  public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_menu, menu); //search setting  MenuItem mSearch = menu.findItem(R.id.action_search);
        SearchView mSearchView = (SearchView) mSearch.getActionView();

        mSearchView.setQueryHint("Search");
        mSearchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() { @Override  public boolean onQueryTextSubmit(String query) { return false;
            } @Override  public boolean onQueryTextChange(String newText) { adapter.getFilter().filter(newText); return false;
            }
        }); return super.onCreateOptionsMenu(menu);
    } @Override  public boolean onOptionsItemSelected(MenuItem item){ switch (item.getItemId()){ case R.id.menu_clear: new AlertDialog.Builder(MainActivity.this)
                        .setMessage("删除全部吗？")
                        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() { @Override  public void onClick(DialogInterface dialog, int which) { dbHelper = new NoteDatabase(context);
                                SQLiteDatabase db = dbHelper.getWritableDatabase();
                                db.delete("notes", null, null);
                                db.execSQL("update sqlite_sequence set seq=0 where name='notes'");
                                refreshListView();
                            }
                        }).setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() { @Override  public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                }).create().show(); break;

        } return super.onOptionsItemSelected(item);
    } public void refreshListView(){

        CRUD op = new CRUD(context);
        op.open(); // set adapter  if (noteList.size() > 0) noteList.clear(); noteList.addAll(op.getAllNotes());
        op.close(); adapter.notifyDataSetChanged();
    } @Override  public void onItemClick(AdapterView<?> parent, View view, int position, long id) { switch (parent.getId()) { case R.id.lv:
                Note curNote = (Note) parent.getItemAtPosition(position);
                Intent intent = new Intent(MainActivity.this, EditActivity.class);
                intent.putExtra("content", curNote.getContent());
                intent.putExtra("id", curNote.getId());
                intent.putExtra("time", curNote.getTime());
                intent.putExtra("mode", 3); // MODE of 'click to edit'  intent.putExtra("tag", curNote.getTag());
                startActivityForResult(intent, 1); //collect data from edit  Log.d(TAG, "onItemClick: "  position); break;
        }
    }
}