Java 调用显示对话框的方法时发生空指针异常
我使用AmbilwarnaColorDialog来选择颜色。所以我加入了Ambilwarna库。我想通过单击图像打开“颜色”对话框。所以我只调用下面的方法。但它显示了空指针异常。有人能帮我吗? 我的代码:Java 调用显示对话框的方法时发生空指针异常,java,android,click,Java,Android,Click,我使用AmbilwarnaColorDialog来选择颜色。所以我加入了Ambilwarna库。我想通过单击图像打开“颜色”对话框。所以我只调用下面的方法。但它显示了空指针异常。有人能帮我吗? 我的代码: int color; void openDialog(boolean supportsAlpha) { AmbilWarnaDialog dialog = new AmbilWarnaDialog(MainActivity.this, color, supp
int color;
void openDialog(boolean supportsAlpha) {
AmbilWarnaDialog dialog = new AmbilWarnaDialog(MainActivity.this,
color, supportsAlpha,
new AmbilWarnaDialog.OnAmbilWarnaListener() {
@Override
public void onOk(AmbilWarnaDialog dialog, int color) {
Toast.makeText(getApplicationContext(), "ok",
Toast.LENGTH_SHORT).show();
MainActivity.this.color = color;
}
@Override
public void onCancel(AmbilWarnaDialog dialog) {
Toast.makeText(getApplicationContext(), "cancel",
Toast.LENGTH_SHORT).show();
}
});
dialog.show();
}
我的意思是:
import yuku.ambilwarna.AmbilWarnaDialog;
LogCat的表现如下:
01-20 10:54:56.260: E/AndroidRuntime(14407): FATAL EXCEPTION: main
01-20 10:54:56.260: E/AndroidRuntime(14407): java.lang.NullPointerException
01-20 10:54:56.260: E/AndroidRuntime(14407): at yuku.ambilwarna.AmbilWarnaDialog.<init>(AmbilWarnaDialog.java:84)
01-20 10:54:56.260: E/AndroidRuntime(14407): at com.example.demofordrawline.MainActivity.openDialog(MainActivity.java:178)
01-20 10:54:56.260: E/AndroidRuntime(14407): at com.example.demofordrawline.MainActivity.onClick(MainActivity.java:251)
01-20 10:54:56.260: E/AndroidRuntime(14407): at android.view.View.performClick(View.java:4212)
01-20 10:54:56.260: E/AndroidRuntime(14407): at android.view.View$PerformClick.run(View.java:17476)
01-20 10:54:56.260: E/AndroidRuntime(14407): at android.os.Handler.handleCallback(Handler.java:800)
01-20 10:54:56.260: E/AndroidRuntime(14407): at android.os.Handler.dispatchMessage(Handler.java:100)
01-20 10:54:56.260: E/AndroidRuntime(14407): at android.os.Looper.loop(Looper.java:194)
01-20 10:54:56.260: E/AndroidRuntime(14407): at android.app.ActivityThread.main(ActivityThread.java:5371)
01-20 10:54:56.260: E/AndroidRuntime(14407): at java.lang.reflect.Method.invokeNative(Native Method)
01-20 10:54:56.260: E/AndroidRuntime(14407): at java.lang.reflect.Method.invoke(Method.java:525)
01-20 10:54:56.260: E/AndroidRuntime(14407): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
01-20 10:54:56.260: E/AndroidRuntime(14407): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
01-20 10:54:56.260: E/AndroidRuntime(14407): at dalvik.system.NativeStart.main(Native Method)
试试这个代码
package yuku.ambilwarna.demo;
import yuku.ambilwarna.AmbilWarnaDialog;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class AmbilWarnaDemoActivity extends Activity {
int color = 0xffffff00;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final Button button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
openDialog();
}
});
}
void openDialog() {
AmbilWarnaDialog dialog = new AmbilWarnaDialog(
AmbilWarnaDemoActivity.this, color,
new AmbilWarnaDialog.OnAmbilWarnaListener() {
@Override
public void onOk(AmbilWarnaDialog dialog, int color) {
AmbilWarnaDemoActivity.this.color = color;
Toast.makeText(getApplicationContext(),
"Color is " + color, Toast.LENGTH_SHORT).show();
}
@Override
public void onCancel(AmbilWarnaDialog dialog) {
Toast.makeText(getApplicationContext(), "cancel",
Toast.LENGTH_SHORT).show();
}
});
dialog.show();
}
}
@VaishaliVaghasiya在哪一行出现错误?您的颜色变量是全局声明的还是在类的内部方法中声明的??您是否正在使用该第三方库??完整文档:是,我全局声明了颜色变量。@VaishaliVaghasiya能否将您的项目演示与库一起发送给我?@VaishaliVaghasiya是否已正确检查您的第三方库项目是否以绿色标记导入,并且在工作区中也是如此?请清理您的项目,然后运行