[英]Imageview in android using base64 string retrieved from firebase
[英]How resize base64 ImageView using java android?
我正在嘗試調整 ImageView 的大小,其中我使用 base64 編碼圖像,僅使用 java,但出現錯誤。 有誰知道一種方法?
我的代碼:
import android.content.Context;
import android.graphics.BitmapFactory;
import android.util.Base64;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.LinearLayout.LayoutParams;
public class kd {
public static void Show(final Context context) {
ImageView iv_image = new ImageView(context);
String base64_img = "my base64 image code here";
byte[] imageAsBytes = Base64.decode(base64_img.getBytes(), 0);
LayoutParams params = (LayoutParams) iv_image.getLayoutParams();
params.width = 50;
params.height = 50;
iv_image.setLayoutParams(params);
iv_image.setImageBitmap(BitmapFactory.decodeByteArray(imageAsBytes, 0, imageAsBytes.length));
}
}
錯誤日志:
FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.my.package/com.my.package.MainActivity}: java.lang.NullPointerException: Attempt to write to field 'int android.view.ViewGroup$LayoutParams.width' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3562)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3723)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2166)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:236)
at android.app.ActivityThread.main(ActivityThread.java:7821)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:621)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:997)
Caused by: java.lang.NullPointerException: Attempt to write to field 'int android.view.ViewGroup$LayoutParams.width' on a null object reference
at com.my.package.kd.Show(kd.java:94)
at com.my.package.MainActivity.onCreate(MainActivity.java:14)
at android.app.Activity.performCreate(Activity.java:8012)
at android.app.Activity.performCreate(Activity.java:7996)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1311)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3535)
我嘗試了幾種更改尺寸的方法,但總是收到一些錯誤,如果有人能幫我一把,我將不勝感激。
您的問題是您的 LayoutParams 是 null,因為您創建的視圖沒有父級。 這意味着 getLayoutParams 將返回 null。 要么先把它放在一個父級中,要么為你的父級創建一個正確類型的 LayoutParams object。
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