安卓学习日记——xUtils

https://github.com/qxbl/xUtils
下载完之后，解压，导入jar包
DbUtils的使用

权限设置

User

package com.example.xutils;

public class User {
    private int id;
    private String name;
    private String email;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public User(String email, String name) {
        this.email = email;
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public User() {
    }


    @Override
    public String toString() {
        return "User{" +
                "email='" + email + '\'' +
                ", id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

public class MainActivity extends AppCompatActivity {
    DbUtils dbUtils;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        dbUtils= DbUtils.create(this,"mydb");
    }

添加

public void saveClick(View v){
        User user=new User("[email protected]","ck");
        try {
            dbUtils.save(user);
            Toast.makeText(this, "save success", Toast.LENGTH_SHORT).show();
        } catch (DbException e) {
            e.printStackTrace();
        }
    }

查询

public void findAllClick(View v){
        try {
            List list=dbUtils.findAll(User.class);
            for (User u:list)
            {
                System.out.println(u);
            }
        } catch (DbException e) {
            e.printStackTrace();
        }
    }

条件查询

 public void selectByClick(View view)
    {
        try {
            User user = dbUtils.findFirst(Selector.from(User.class).where("name","=","ck"));
            Toast.makeText(this,user.toString(),Toast.LENGTH_LONG).show();
        } catch (DbException e) {
            e.printStackTrace();
        }
    }

更新

public void updateClick(View view)
    {
        User user=new User();
        user.setId(1);
        user.setEmail("[email protected]");
        user.setName("chenke");
        try {
            dbUtils.update(user,"email","name");
            Toast.makeText(this,"更新成功",Toast.LENGTH_LONG).show();
        } catch (DbException e) {
            e.printStackTrace();
        }
    }

删除

public void deleteClick(View view)
    {
        try {
            dbUtils.delete(User.class, WhereBuilder.b("id","=","1"));
            Toast.makeText(this,"删除成功",Toast.LENGTH_LONG).show();
        } catch (DbException e) {
            e.printStackTrace();
        }
    }

ViewUtils的使用

public class MainActivity extends AppCompatActivity {
    DbUtils dbUtils;

    @ViewInject(R.id.textView_data)
    private TextView textView_data;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ViewUtils.inject(this); //注入view和事件
        dbUtils= DbUtils.create(this,"mydb");
    }

@OnClick(R.id.button_show)
    public void show(View v){
        textView_data.setText("viewUtils的使用");
    }

HttpUtils由于没去写服务器，所以这边不好测试，就没弄了

package com.example.xutils;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

import com.lidroid.xutils.HttpUtils;
import com.lidroid.xutils.ViewUtils;
import com.lidroid.xutils.exception.HttpException;
import com.lidroid.xutils.http.RequestParams;
import com.lidroid.xutils.http.ResponseInfo;
import com.lidroid.xutils.http.callback.RequestCallBack;
import com.lidroid.xutils.http.client.HttpRequest;
import com.lidroid.xutils.view.annotation.ViewInject;
import com.lidroid.xutils.view.annotation.event.OnClick;

public class Main2Activity extends AppCompatActivity {
    @ViewInject(R.id.editText_username)
    EditText editText_username;
    @ViewInject(R.id.editText_password)
    EditText editText_password;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        ViewUtils.inject(this);//注入view和事件
    }

    @OnClick(R.id.button_login)
    public void login(View v){
        String username=editText_username.getText().toString();
        String password=editText_password.getText().toString();

        HttpUtils httpUtils=new HttpUtils();
        String url="";  //服务器地址
        RequestParams params=new RequestParams();
        params.addQueryStringParameter("username",username);  //服务器那边对应的参数名称
        params.addBodyParameter("password",password); //服务器那边对应的参数名称
        httpUtils.send(HttpRequest.HttpMethod.POST, url, params, new RequestCallBack() {

            @Override
            public void onSuccess(ResponseInfo responseInfo) {
            String result=responseInfo.result;
            if ("1".equals(result)){
                Toast.makeText(Main2Activity.this, "登录成功", Toast.LENGTH_SHORT).show();
            }else {
                Toast.makeText(Main2Activity.this, "登录失败", Toast.LENGTH_SHORT).show();
            }
            }

            @Override
            public void onFailure(HttpException e, String s) {
                Toast.makeText(Main2Activity.this, s, Toast.LENGTH_SHORT).show();
            }
        });
    }

}

使用HttpUtils时出现了“无法访问HttpRequestBase 找不到org.apache.http.client.methods.HttpRequestBase的类文件”这个错误，原因是
android 6.0(api 23) SDK，Android的网络请求强制使用HttpUrlConnection,并且SDK中也已经移除了HttpClient。
解决办法
在build.gradle中添加
android {

useLibrary'org.apache.http.legacy'

｝
就可以了