EditActivity

public class EditActivity extends BaseActivity {
    private EditText et;
    private Context context = this;
    private Toolbar myToolbar;
    private String old_content = "";
    private String old_time = "";
    private int old_Tag = 1;
    private long id = 0;
    private int openMode = 0;
    private int tag = 1;
    private boolean tagChange = false;
    public Intent intent=new Intent();//Message to be sent


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.edit_layout);
        myToolbar=findViewById(R.id.edit_toolbar);
        setSupportActionBar( myToolbar );
        getSupportActionBar().setHomeButtonEnabled(true);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);


        myToolbar.setNavigationOnClickListener(new View.OnClickListener() {//对状态栏返回键进行点击设置
            @Override
            public void onClick(View v) {
                autoSetMessage();
                setResult(RESULT_OK,intent);
                finish();
            }
        });
        et=findViewById(R.id.et);

        Intent getIntent=getIntent();
        openMode=getIntent().getIntExtra("mode",0);
        Log.d("Edit","openMode(onCreate)="+openMode);
        if (openMode == 3) {//打开已存在的note
            id = getIntent.getLongExtra("id", 0);
            old_content = getIntent.getStringExtra("content");
            old_time = getIntent.getStringExtra("time");
            old_Tag = getIntent.getIntExtra("tag", 1);
            et.setText(old_content);
            et.setSelection(old_content.length());

        }

        Log.d("Edit","onCreate");

    }
    public boolean onKeyDown(int keyCode, KeyEvent event){//设置返回键，Home键
        Log.d("Edit","dateToStr");
        if (keyCode==KeyEvent.KEYCODE_HOME){
            return true;
        }
        else if (keyCode==KeyEvent.KEYCODE_BACK){
            Log.d("Edit","back");
            autoSetMessage();
            setResult(RESULT_OK,intent);
            finish();
            return true;
        }
        return super.onKeyDown(keyCode,event);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.edit_menu,menu);
        return super.onCreateOptionsMenu(menu);
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch (item.getItemId()){
            case R.id.delete:
                new AlertDialog.Builder(EditActivity.this)
                        .setMessage("删除吗？")
                        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                if (openMode==4){//new note
                                    intent.putExtra("mode",-1);
                                    setResult(RESULT_OK,intent);
                                }else{//existing note
                                    intent.putExtra("mode",2);
                                    intent.putExtra("id",id);
                                    setResult(RESULT_OK,intent);
                                }
                                finish();
                            }
                        }).setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();//关闭当期对话框
                    }
                }).create().show();
                break;
        }
        return super.onOptionsItemSelected(item);
    }

    private void autoSetMessage() {//进行修改或创建新的笔记
        Log.d("Edit","openMode="+openMode);
        if (openMode==4){//新建的
            if (et.getText().toString().length()==0){//什么也没写
                intent.putExtra("mode",-1);//什么也没干
            }else {
                intent.putExtra("mode",0);//创建新笔记
                intent.putExtra("content",et.getText().toString());
                intent.putExtra("time",dateToStr());
                intent.putExtra("tag",tag);
            }
        }else{
            if(et.getText().toString().equals(old_content)&& !tagChange){//未修改
                intent.putExtra("mode","-1");
            }else{
                intent.putExtra("mode",1);
                intent.putExtra("content",et.getText().toString());
                intent.putExtra("id",id);
                intent.putExtra("time",dateToStr());
                intent.putExtra("tag",tag);
            }
        }
    }

    public String dateToStr(){
        Log.d("Edit","dateToStr");
        Date date=new Date(System.currentTimeMillis());
        @SuppressLint("SimpleDateFormat") SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
        return simpleDateFormat.format(date);
    }

    @Override
    public void needRefresh() {//本页面刷新
        setNightMode();
        Intent intent=new Intent(this,EditActivity.class);
        startActivity(intent);
    }
}