我正在模仿此thread中的代码,以创建一个可重复使用的点击事件来触发浏览器。我想在实例化类时传递自定义URL目标。该示例在eclipse中没有明显错误,但在启动时崩溃:
btn.setOnClickListener(new ButtonInternetAccess("http://google.com"));
错误应来自此行
ButtonInternetAccess
因为没有那条线它可以正常工作。
类public class ItemActivity extends ActionBarActivity{
private static final View View = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item);
Bundle b = i.getExtras();
Button btn = (Button) findViewById(R.id.button_internet_access);
btn.setOnClickListener(new ButtonInternetAccess("http://google.com"));
}
}
是否无法返回导致null值的onClickListener?我该如何解决这个问题?
主要活动:
public class ButtonInternetAccess extends Activity implements OnClickListener {
String url;
public ButtonInternetAccess(String url) {
this.url = url;
}
public void onClick(View v) {
try {
Intent callIntent = new Intent(Intent.ACTION_CALL);
callIntent.setData(Uri.parse(url));
startActivity(callIntent); // No Error here
System.out.println(url);
} catch (ActivityNotFoundException activityException) {
Log.e("Calling a Phone Number", "Call failed", activityException);
}
}
}
按钮类:
<TextView
android:id="@+id/response"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="" />
<include android:id="@+id/header" layout="@layout/button_internet_access">
布局/ activity_item
<Button xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/button_internet_access"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="go out" />
布局/ button_internet_access:
02-19 12:45:57.416: E/AndroidRuntime(12465): FATAL EXCEPTION: main
02-19 12:45:57.416: E/AndroidRuntime(12465): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.app/com.app.ItemActivity}: java.lang.NullPointerException
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.app.ActivityThread.access$600(ActivityThread.java:130)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.os.Handler.dispatchMessage(Handler.java:99)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.os.Looper.loop(Looper.java:137)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.app.ActivityThread.main(ActivityThread.java:4745)
02-19 12:45:57.416: E/AndroidRuntime(12465): at java.lang.reflect.Method.invokeNative(Native Method)
02-19 12:45:57.416: E/AndroidRuntime(12465): at java.lang.reflect.Method.invoke(Method.java:511)
02-19 12:45:57.416: E/AndroidRuntime(12465): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
02-19 12:45:57.416: E/AndroidRuntime(12465): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
02-19 12:45:57.416: E/AndroidRuntime(12465): at dalvik.system.NativeStart.main(Native Method)
02-19 12:45:57.416: E/AndroidRuntime(12465): Caused by: java.lang.NullPointerException
02-19 12:45:57.416: E/AndroidRuntime(12465): at com.app.ItemActivity.onCreate(ItemActivity.java:29)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.app.Activity.performCreate(Activity.java:5008)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
02-19 12:45:57.416: E/AndroidRuntime(12465): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
错误:
public class Internet implements OnClickListener {
private String url;
private Context context;
public Internet(Context context, String url) {
this.context = context;
this.url = url;
}
@Override
public void onClick(View v) {
if (!url.contains("http://")){
url = "http://"+url;
}
Intent callIntent = new Intent(Intent.ACTION_VIEW);
callIntent.setData(Uri.parse(url));
context.startActivity(callIntent);
}
}
更新:
我已设法在此link之后制作插件。
最后的工作:
班级互联网:
public class StyleButton extends Button{
public StyleButton(Context context) {
super(context);
}
public StyleButton(Context context, AttributeSet attrs) {
super(context, attrs);
initStyleButton(attrs);
}
public StyleButton(Context context, AttributeSet attrs, int defStyle,String url) {
super(context, attrs, defStyle);
initStyleButton(attrs);
}
private void initStyleButton(AttributeSet attrs){
TypedArray a = getContext().obtainStyledAttributes(attrs,R.styleable.style_Button);
String Text1 = a.getString(R.styleable.style_Button_myText_1);
String Text2 = a.getString(R.styleable.style_Button_myText_2);
setText(Text1 + "\n" + Text2);
String url = a.getString(R.styleable.style_Button_url);
System.out.println(url);
setOnClickListener(new Internet(getContext(),url));
a.recycle();
}
}
Class StyleButton:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:stylebutton= "http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:id="@+id/response"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=""/>
<com.button.StyleButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
stylebutton:myText_1="My Text 1"
stylebutton:myText_2="My Text 2"
stylebutton:url="www.google.com"
/>
<com.button.StyleButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
stylebutton:myText_1="Hello!"
stylebutton:myText_2="It's a Style Button:)"
stylebutton:url="www.yahoo.com"
/>
/布局/ item_activity
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="style_Button">
<attr name="myText_1" format="string" />
<attr name="myText_2" format="string" />
<attr name="url" format="string" />
</declare-styleable>
</resources>
/value/attr.xml
<button class="btn btn-default" id="1" onclick="APP.agregarNumeros()">1</button>
<button class="btn btn-default" id="2" onclick="APP.agregarNumeros()">2</button>
<p id="resultado"></p>
<script>
var counterAPP = {
agregarNumeros:function(){
var resultado = "";
if ($("#1")) {
resultado += $("#resultado").text("1");
}
else if ($("#2")) {
resultado += $("#resultado").text("2");
}
}
};
window.APP = counterAPP;
答案 0 :(得分:1)
将按钮类更改为;
{{1}}
答案 1 :(得分:1)
你的setOnClickListener应如下所示:
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
try {
Intent callIntent = new Intent(Intent.ACTION_CALL);
callIntent.setData(Uri.parse("http://google.com"));
startActivity(callIntent); // No Error here
System.out.println(url);
} catch (ActivityNotFoundException activityException) {
Log.e("Calling a Phone Number", "Call failed", activityException);
}
}
});
您似乎不需要将URL发送到另一个类,因为您可以对ItemActivity
本身执行相同的操作。
编辑:如果您想要将一个类格式化,请将ButtonInternetAccess更新为以下方式:
public class ButtonInternetAccess implements OnClickListener {
String url;
Context mContext;
public ButtonInternetAccess(Context mContext,String url) {
this.url = url;
this.mContext=mContext;
}
public void onClick(View v) {
try {
Intent callIntent = new Intent(Intent.ACTION_CALL);
callIntent.setData(Uri.parse(url));
mContext.startActivity(callIntent);
System.out.println(url);
} catch (ActivityNotFoundException activityException) {
Log.e("Calling a Phone Number", "Call failed", activityException);
}
}
}
答案 2 :(得分:1)
创建您的custom button并在项目中使用它,以便可以全局使用它。
public class ButtonInternetAccess extends UIButton implements OnClickListener {
String url;
Context mContext;
public ButtonInternetAccess(Context context, AttributeSet attrs,String url) {
super(context, attrs);
this.url = url;
this.mContext=mContext;
// TODO Auto-generated constructor stub
}
// initialize button and add click listener here.
}
您可以将该按钮添加到xml中,如
<yourpackagename.ButtonInternetAccess
height=""
width = ""
other properties to include
/>
希望这会有所帮助。