Android实现风蓝记事本（5）：修改记事功能

今天药忘吃喽~ 2022-05-24 04:16 233阅读 0赞

package com.example.notes;
    
    import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.logging.SimpleFormatter;
    
    
    
    import android.app.Activity;
    import android.app.Dialog;
    import android.content.Intent;
    import android.content.SharedPreferences;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.os.Bundle;
    import android.os.Environment;
    import android.text.Selection;
    import android.text.Spannable;
    import android.util.Log;
    import android.view.KeyEvent;
    import android.view.Menu;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.ImageButton;
    import android.widget.LinearLayout;
    import android.widget.TextView;
    import android.widget.Toast;
    
    public class Update extends Activity {
        private LinearLayout layout;      //布局
        private TextView update_title;    //标题栏
        private EditText update_content;      //输入框
    
        private ImageButton backBtn;   //返回
        private ImageButton deleteBtn; //删除
        private ImageButton confirmBtn;    //确认
    
        private Dialog delDialog;     //删除对话框
        private Integer s_id;        //记事ID
        private String title;        //标题
        private String content;          //内容
        private DatabaseManage dm = null;// 数据库管理对象
        private Cursor cursor = null;
        private int background;//背景
        private  SharedPreferences sp;//存储数据
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.update);
    
    
            layout=(LinearLayout)findViewById(R.id.update);
            dm = new DatabaseManage(this);// 数据库操作对象
            update_title=(TextView)findViewById(R.id.update_title);
            update_content=(EditText)findViewById(R.id.update_content);
            backBtn=(ImageButton)findViewById(R.id.back_btn);
            deleteBtn=(ImageButton)findViewById(R.id.delete_btn);
            confirmBtn=(ImageButton)findViewById(R.id.confirm_btn);
            background = R.drawable.skin_first;
            getBackground();
            Intent intent=getIntent();    //恢复未保存数据
            HashMap<String, Object> map=(HashMap<String, Object>) intent.getSerializableExtra("data");
            title=(String) map.get("title");
            content=(String) map.get("content");
            s_id=(Integer)map.get("id");
            update_title.setText(title);
            update_content.setText(content);
    
            ImageButton[] btns={backBtn,deleteBtn,confirmBtn};
            for(ImageButton btn:btns)
                btn.setOnClickListener(click);
    
        }
        //设置背景
        private void getBackground(){
            sp=getSharedPreferences("backgrounds", 0);
            background=sp.getInt("background",background);
            layout.setBackgroundResource(background);
        }
    
        private OnClickListener click=new OnClickListener(){
            @Override
            public void onClick(View v) {
                switch(v.getId()){
                    case R.id.back_btn:
                        back();
                        break;
                    case R.id.delete_btn:
                        delete();
                        break;
                    case R.id.confirm_btn:
                        save();
                        break;
                }
            }
    
        };
    
        private void save(){
            String n_content=update_content.getText().toString().trim();
            SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            String time=df.format(new Date());
            if(n_content!=null){
                dm.open();
                int flag=dm.update(s_id, title, n_content, time);
                if(flag>0){
                    Toast.makeText(Update.this, R.string.note_saved, Toast.LENGTH_SHORT).show();
                    Intent intent=new Intent(Update.this,MainActivity.class);
                    startActivity(intent);
                    finish();
                }else{
                    Toast.makeText(Update.this, R.string.note_null, Toast.LENGTH_SHORT).show();//弹出消息
                }
            }else{
                Toast.makeText(Update.this, R.string.note_null, Toast.LENGTH_SHORT).show();
            }
    
    
        }
    
        private void delete(){    //删除记事
            View deleteView = View.inflate(this, R.layout.deletenote, null);
            delDialog=new Dialog(this,R.style.dialog);
            delDialog.setContentView(deleteView);
            Button yesBtn=(Button)deleteView.findViewById(R.id.delete_yes);
            Button noBtn=(Button)deleteView.findViewById(R.id.delete_no);
            yesBtn.setOnClickListener(new OnClickListener(){
                @Override
                public void onClick(View view) {
                    dm.open();
                    dm.delete(s_id);
                    Toast.makeText(Update.this, R.string.note_deleted, Toast.LENGTH_SHORT).show();
                    delDialog.dismiss();
                    Intent intent=new Intent(Update.this,MainActivity.class);
                    startActivity(intent);
                    finish();
                }
            });
            noBtn.setOnClickListener(new OnClickListener(){
                @Override
                public void onClick(View view) {
                    delDialog.dismiss();
                }
            });
            delDialog.show();
        }
    
        private void back(){
            Intent intent=new Intent(Update.this,MainActivity.class);
            startActivity(intent);
            finish();
        }
        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            return true;
        }
    }

用到的布局：  setContentView(R.layout.update)-->update.xml

# 注：源码下载：[https://download.csdn.net/download/weixin\_39220472/10426057][https_download.csdn.net_download_weixin_39220472_10426057] #

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[https_download.csdn.net_download_weixin_39220472_10426057]: https://download.csdn.net/download/weixin_39220472/10426057