java - gradle显示兼容性错误

Question

我创建了 Android 应用程序。我想显示来 self 的 aws mysql 数据库的数据。我写了以下代码:

package com.example.yash.car2;

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;

import  java.sql.*;


public class MainActivity extends AppCompatActivity{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        init();
    }



    public Connection CreateDBconn()
    {
        try
        {
            String DRIVER_NAME = "com.mysql.jdbc.Driver";
            String HOST_NAME = "firstdb.cqmpw4u1tyz3.us-west-2.rds.amazonaws.com";
            String PORT_NUMBER = "3306";
            String DB_NAME = "test_master";
            String USER_NAME = "*****";
            String PASSWORD = "*****";
            String URL="jdbc:mysql://firstdb.cqmpw4u1tyz3.us-west-2.rds.amazonaws.com/test_master";
            Class.forName(DRIVER_NAME);
            Connection conn =   DriverManager.getConnection(URL,USER_NAME,PASSWORD);
            return conn;

        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }

    public void init() {
try
{
        Connection c=CreateDBconn();
        String query="SELECT * FROM STUD";
        Statement st=c.createStatement();
        ResultSet rs=st.executeQuery(query);

        TableLayout stk = (TableLayout) findViewById(R.id.TL);
        TableRow tbrow0 = new TableRow(this);
        TextView tv0 = new TextView(this);
        tv0.setText(" Sl.No ");
        tv0.setTextColor(Color.WHITE);
        tbrow0.addView(tv0);
        TextView tv1 = new TextView(this);
        tv1.setText(" Last Name ");
        tv1.setTextColor(Color.WHITE);
        tbrow0.addView(tv1);
        TextView tv2 = new TextView(this);
        tv2.setText(" First Name ");
        tv2.setTextColor(Color.WHITE);
        tbrow0.addView(tv2);
        TextView tv3 = new TextView(this);
        tv3.setText(" Age ");
        tv3.setTextColor(Color.WHITE);
        tbrow0.addView(tv3);
        TextView tv4 = new TextView(this);
        tv4.setText(" Branch ");
        tv4.setTextColor(Color.WHITE);
        tbrow0.addView(tv4);
        stk.addView(tbrow0);

        while (rs.next()) {
            TableRow tbrow = new TableRow(this);
            TextView t1v = new TextView(this);
            t1v.setText(rs.getInt("id"));
            t1v.setTextColor(Color.WHITE);
            t1v.setGravity(Gravity.CENTER);
            tbrow.addView(t1v);
            TextView t2v = new TextView(this);
            t2v.setText(rs.getString("LastName"));
            t2v.setTextColor(Color.WHITE);
            t2v.setGravity(Gravity.CENTER);
            tbrow.addView(t2v);
            TextView t3v = new TextView(this);
            t3v.setText(rs.getString("FirstName"));
            t3v.setTextColor(Color.WHITE);
            t3v.setGravity(Gravity.CENTER);
            tbrow.addView(t3v);
            TextView t4v = new TextView(this);
            t4v.setText(rs.getInt("Age"));
            t4v.setTextColor(Color.WHITE);
            t4v.setGravity(Gravity.CENTER);
            tbrow.addView(t4v);
            TextView t5v=new TextView(this);
            t5v.setText(rs.getString("Branch"));
            t5v.setTextColor(Color.WHITE);
            t5v.setGravity(Gravity.CENTER);
            tbrow.addView(t5v);
            stk.addView(tbrow);
        }}
catch (Exception e)
{
    e.printStackTrace();
}

    }}

我的代码显示以下错误:

1:Error:Error converting bytecode to dex: Cause: Dex cannot parse version 52 byte code. This is caused by library dependencies that have been compiled using Java 8 or above. If you are using the 'java' gradle plugin in a library submodule add targetCompatibility = '1.7' sourceCompatibility = '1.7' to that submodule's build.gradle file.

2.Error:Execution failed for task ':app:transformClassesWithDexForDebug'.

com.android.build.api.transform.TransformException: java.lang.RuntimeException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.ide.common.process.ProcessException: Return code 1 for dex process

我对所有数据库的事情都很陌生。我猜问题出在 java.sql 的导入中，但我没有得到任何解决方案。

请帮忙!

Answer 1

您需要使用 Java 8，因为您的代码依赖于 Java 8 依赖项。

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.2"

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

也使用最新的 gradle 插件。

classpath 'com.android.tools.build:gradle:3.3.3'