[英]android studio picasso java.lang.IllegalArgumentException: Target must not be null
[英]java.lang.IllegalArgumentException: Target must not be null
当我将图像 url 传递给 Picasso 时,它会显示错误“目标不能为空”。 当我使用 Picasso 从 url 获取图像时,它会显示错误。 甚至我分配给图像的 id 也是正确的。 最后我用静态图像替换了图像 url,虽然我收到了同样的错误。
这是我的代码:
public class MainScreen extends AppCompatActivity {
private ImageView user_profile_pic,img2;
private ImageView like_button,dislike_button,location_button,refresh;
private ArrayList<String> al;
private ArrayAdapter<String> arrayAdapter;
private int i;
private SwipeFlingAdapterView flingContainer;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_screen);
//Setting
user_profile_pic=(ImageView)findViewById(R.id.profile_image);
img2=(ImageView)findViewById(R.id.img2);
//Picasso.with(getApplicationContext()).load("https://pbs.twimg.com/profile_images/596282530652753921/bPf8NmOs.jpg").into(user_profile_pic);
//Picasso.with(getApplicationContext()).load(android.R.drawable.btn_star).into(img);
Picasso.with(getApplicationContext()).load("https://pbs.twimg.com/profile_images/596282530652753921/bPf8NmOs.jpg")
.placeholder(android.R.drawable.btn_star)
.error(android.R.drawable.btn_star)
.into(img2);
flingContainer = (SwipeFlingAdapterView) findViewById(R.id.frame);
al = new ArrayList<>();
al.add("php");
al.add("c");
al.add("python");
al.add("java");
al.add("html");
al.add("c++");
al.add("css");
al.add("javascript");
arrayAdapter = new ArrayAdapter<>(this, R.layout.custom_user_details, R.id.helloText, al );
flingContainer.setAdapter(arrayAdapter);
flingContainer.setFlingListener(new SwipeFlingAdapterView.onFlingListener() {
@Override
public void removeFirstObjectInAdapter() {
Log.d("LIST", "removed object!");
al.remove(0);
arrayAdapter.notifyDataSetChanged();
}
@Override
public void onLeftCardExit(Object dataObject) {
Toast.makeText(getApplicationContext(),"Left !",Toast.LENGTH_SHORT).show();
}
@Override
public void onRightCardExit(Object dataObject) {
Toast.makeText(getApplicationContext(),"Right !",Toast.LENGTH_SHORT).show();
}
@Override
public void onAdapterAboutToEmpty(int itemsInAdapter) {
al.add("XML ".concat(String.valueOf(i)));
arrayAdapter.notifyDataSetChanged();
Log.d("LIST", "notified");
i++;
}
@Override
public void onScroll(float scrollProgressPercent) {
try
{
View view = flingContainer.getSelectedView();
view.findViewById(R.id.item_swipe_right_indicator).setAlpha(scrollProgressPercent < 0 ? -scrollProgressPercent : 0);
view.findViewById(R.id.item_swipe_left_indicator).setAlpha(scrollProgressPercent > 0 ? scrollProgressPercent : 0);
}
catch (NullPointerException e) {
Log.e("tag", "NullPointerException" + e);
}
}
});
//flingContainer.getTopCardListener().selectRight(); To remove view from right side while pressing button
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main_screen, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
这就是我的xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_gravity="center"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="80">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/img2"
android:src="@android:drawable/btn_star"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="20"
android:padding="8dp"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dp"
android:layout_height="40dp"
android:layout_weight="1"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Vimal, "
android:id="@+id/helloText"
android:textColor="@android:color/black"
android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="23"
android:textColor="@android:color/black"
android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"/>
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="40dp"
android:layout_weight="1"
android:orientation="horizontal">
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_weight="1">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:src="@android:drawable/btn_dialog"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:textSize="25sp"
android:layout_marginLeft="5dp"
android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"
android:gravity="center"/>
</LinearLayout>
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_weight="1">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:src="@android:drawable/btn_dialog"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:textSize="25sp"
android:layout_marginLeft="5dp"
android:layout_gravity="center"
android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
<View
android:id="@+id/item_swipe_left_indicator"
android:alpha="0"
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_margin="10dp"
android:background="#A5F" />
<View
android:id="@+id/item_swipe_right_indicator"
android:alpha="0"
android:layout_width="20dp"
android:layout_height="20dp"
android:layout_margin="10dp"
android:layout_gravity="right"
android:background="#5AF" />
</FrameLayout>
img2
为空,您将其传递给into
函数。
在img2=(ImageView)findViewById(R.id.img2);
之后添加空检查检查它何时停止为空,或者在您测试时它是否保持为空,或者只是确认它为空。
检查您的布局 ID 并确保它们适用于所有配置,并确保您指定了@+id/img2
。
你确定加载正确的布局吗? 因为您在 Java 文件中有 R.id.profile_image,但我没有在您的 xml 文件中找到该 id。
尝试将其更改为..
Picasso.with(MainScreen.this).load("https://pbs.twimg.com/profile_images/596282530652753921/bPf8NmOs.jpg")
.placeholder(android.R.drawable.btn_star)
.error(android.R.drawable.btn_star)
.into(img2);
还要确保您使用的是activity_main_screen.xml
布局并检查 id 是否存在 img2。
您无法使用 Picasso 库从https下载图像。 你可以使用这个库。
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