Android - PHP / MYSQL example



我是android 的初学者

我使用的是安卓版本1.0

我试图从网页上复制代码并修改

hishttp://www.tutorialspoint.com/android/android_php_mysql.htm

my src/com.example.phpmysql/MainActivity.java

package com.example.a014.phpmysql;
import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends Activity {
private EditText usernameField,passwordField;
private TextView status,role,method;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
usernameField = (EditText)findViewById(R.id.editText1);
passwordField = (EditText)findViewById(R.id.editText2);
status = (TextView)findViewById(R.id.textView6);
role = (TextView)findViewById(R.id.textView7);
method = (TextView)findViewById(R.id.textView9);
}

public void login(View view){
String username = usernameField.getText().toString();
String password = passwordField.getText().toString();
method.setText("Get Method");
new SigninActivity(this,status,role,0).execute(username,password);
}
public void loginPost(View view){
String username = usernameField.getText().toString();
String password = passwordField.getText().toString();
method.setText("Post Method");
new SigninActivity(this,status,role,1).execute(username,password);
}
}

my src/com.example.phpmysql/SigninActivity.java

package com.example.a014.phpmysql;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URI;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.TextView;
public class SigninActivity  extends AsyncTask{
private TextView statusField,roleField;
private Context context;
private int byGetOrPost = 0;
//flag 0 means get and 1 means post.(By default it is get.)
public SigninActivity(Context context,TextView statusField,TextView roleField,int flag) {
this.context = context;
this.statusField = statusField;
this.roleField = roleField;
byGetOrPost = flag;
}
protected void onPreExecute(){
}
@Override
protected String doInBackground(String... arg0) {
if(byGetOrPost == 0){ //means by Get Method
try{
String username = (String)arg0[0];
String password = (String)arg0[1];
String link = "http://myphpmysqlweb.hostei.com/login.php?username="+username+"& password="+password;
URL url = new URL(link);
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI(link));
HttpResponse response = client.execute(request);
BufferedReader in = new BufferedReader(new
InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String line="";
while ((line = in.readLine()) != null) {
sb.append(line);
break;
}
in.close();
return sb.toString();
} catch(Exception e){
return new String("Exception: " + e.getMessage());
}
} else{
try{
String username = (String)arg0[0];
String password = (String)arg0[1];
String link="http://myphpmysqlweb.hostei.com/loginpost.php";
String data  = URLEncoder.encode("username", "UTF-8") + "=" +
URLEncoder.encode(username, "UTF-8");
data += "&" + URLEncoder.encode("password", "UTF-8") + "=" +
URLEncoder.encode(password, "UTF-8");
URL url = new URL(link);
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write( data );
wr.flush();
BufferedReader reader = new BufferedReader(new
InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
// Read Server Response
while((line = reader.readLine()) != null) {
sb.append(line);
break;
}
return sb.toString();
} catch(Exception e){
return new String("Exception: " + e.getMessage());
}
}
}
@Override
protected void onPostExecute(String result){
this.statusField.setText("Login Successful");
this.roleField.setText(result);
}
}

我的建筑.gradle

apply plugin: 'com.android.application'
android {
useLibrary 'org.apache.http.legacy'
compileSdkVersion 28
defaultConfig {
applicationId "com.example.a014.phpmysql"
minSdkVersion 17
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
implementation 'org.jbundle.util.osgi.wrapped:org.jbundle.util.osgi.wrapped.org.apache.http.client:4.1.2'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
implementation 'com.android.volley:volley:1.1.0'
}

我的activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/editText1"
android:layout_alignRight="@+id/editText1"
android:ems="10"
android:inputType="textPassword"
tools:layout_editor_absoluteX="85dp"
tools:layout_editor_absoluteY="90dp"></EditText>
<EditText
android:id="@+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:ems="10"
tools:layout_editor_absoluteX="85dp"
tools:layout_editor_absoluteY="164dp">
<requestFocus android:layout_width="wrap_content" />
</EditText>
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/editText1"
android:layout_alignParentLeft="true"
android:text="@string/Username"
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="105dp" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:text="@string/App"
android:textAppearance="?android:attr/textAppearanceLarge"
tools:layout_editor_absoluteX="136dp"
tools:layout_editor_absoluteY="22dp" />
<TextView
android:id="@+id/textView7"
android:layout_width="wrap_content"
android:layout_height="0dp"
android:layout_alignLeft="@+id/textView6"
android:layout_alignBottom="@+id/textView5"
android:text="@string/Role"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textSize="10sp"
tools:layout_editor_absoluteX="136dp"
tools:layout_editor_absoluteY="432dp" />
<TextView
android:id="@+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView6"
android:layout_toLeftOf="@+id/editText1"
android:text="@string/LoginRole"
tools:layout_editor_absoluteX="7dp"
tools:layout_editor_absoluteY="345dp" />
<TextView
android:id="@+id/textView8"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/textView6"
android:layout_alignLeft="@+id/textView5"
android:text="@string/method"
tools:layout_editor_absoluteX="7dp"
tools:layout_editor_absoluteY="428dp" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/button1"
android:layout_alignLeft="@+id/textView8"
android:text="@string/LoginStatus"
tools:layout_editor_absoluteX="7dp"
tools:layout_editor_absoluteY="383dp" />

<TextView
android:id="@+id/textView6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/textView4"
android:layout_centerHorizontal="true"
android:text="@string/Status"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textSize="10sp"
tools:layout_editor_absoluteX="136dp"
tools:layout_editor_absoluteY="383dp" />
<TextView
android:id="@+id/textView9"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView6"
android:layout_alignBottom="@+id/textView8"
android:text="@string/Choose"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textSize="10sp"
tools:layout_editor_absoluteX="136dp"
tools:layout_editor_absoluteY="345dp" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toRightOf="@+id/textView6"
android:onClick="loginPost"
android:text="@string/LoginPost"
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="260dp" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/button2"
android:layout_alignLeft="@+id/textView2"
android:layout_alignBottom="@+id/button2"
android:onClick="login"
android:text="@string/LoginGet"
tools:layout_editor_absoluteX="238dp"
tools:layout_editor_absoluteY="260dp" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/editText2"
android:layout_alignBottom="@+id/editText2"
android:layout_alignParentLeft="true"
android:text="@string/Password"
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="179dp" />

</android.support.constraint.ConstraintLayout>

我的AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.a014.phpmysql">
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name="com.example.a014.phpmysql.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

我不断收到错误信息

我尝试过谷歌,但解决方案不适用

Error running 'app': Gradle project sync failed. Please fix your project and try again

麻烦大师告诉我如何纠正错误,这样他就可以运行

尝试以下步骤

  1. 转到文件->使缓存无效/重新启动
  2. 关闭Android Studio
  3. 重命名/删除用户主目录中的.gradle文件夹
  4. 重新启动Android Studio(它将下载渐变元数据和数据(
  5. 渐变构建成功
  6. 重建项目。完成

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